diff --git a/networksecurity/service/src/com/android/server/net/ct/CertificateTransparencyDownloader.java b/networksecurity/service/src/com/android/server/net/ct/CertificateTransparencyDownloader.java
index c9694d1..c679ab8 100644
--- a/networksecurity/service/src/com/android/server/net/ct/CertificateTransparencyDownloader.java
+++ b/networksecurity/service/src/com/android/server/net/ct/CertificateTransparencyDownloader.java
@@ -27,8 +27,6 @@
 import static com.android.server.net.ct.CertificateTransparencyStatsLog.CERTIFICATE_TRANSPARENCY_LOG_LIST_UPDATE_FAILED__FAILURE_REASON__FAILURE_VERSION_ALREADY_EXISTS;
 import static com.android.server.net.ct.CertificateTransparencyStatsLog.CERTIFICATE_TRANSPARENCY_LOG_LIST_UPDATE_FAILED__FAILURE_REASON__PENDING_WAITING_FOR_WIFI;
 
-import static java.nio.charset.StandardCharsets.UTF_8;
-
 import android.annotation.RequiresApi;
 import android.app.DownloadManager;
 import android.content.BroadcastReceiver;
@@ -43,13 +41,12 @@
 
 import com.android.server.net.ct.DownloadHelper.DownloadStatus;
 
-import org.json.JSONException;
-import org.json.JSONObject;
-
 import java.io.IOException;
 import java.io.InputStream;
 import java.security.GeneralSecurityException;
 import java.security.InvalidKeyException;
+import java.util.ArrayList;
+import java.util.List;
 
 /** Helper class to download certificate transparency log files. */
 @RequiresApi(Build.VERSION_CODES.VANILLA_ICE_CREAM)
@@ -61,9 +58,10 @@
     private final DataStore mDataStore;
     private final DownloadHelper mDownloadHelper;
     private final SignatureVerifier mSignatureVerifier;
-    private final CertificateTransparencyInstaller mInstaller;
     private final CertificateTransparencyLogger mLogger;
 
+    private final List<CompatibilityVersion> mCompatVersions = new ArrayList<>();
+
     private boolean started = false;
 
     CertificateTransparencyDownloader(
@@ -71,25 +69,27 @@
             DataStore dataStore,
             DownloadHelper downloadHelper,
             SignatureVerifier signatureVerifier,
-            CertificateTransparencyInstaller installer,
             CertificateTransparencyLogger logger) {
         mContext = context;
         mSignatureVerifier = signatureVerifier;
         mDataStore = dataStore;
         mDownloadHelper = downloadHelper;
-        mInstaller = installer;
         mLogger = logger;
     }
 
+    void addCompatibilityVersion(CompatibilityVersion compatVersion) {
+        mCompatVersions.add(compatVersion);
+    }
+
     void start() {
         if (started) {
             return;
         }
-        mInstaller.addCompatibilityVersion(Config.COMPATIBILITY_VERSION);
         mContext.registerReceiver(
                 this,
                 new IntentFilter(DownloadManager.ACTION_DOWNLOAD_COMPLETE),
                 Context.RECEIVER_EXPORTED);
+        mDataStore.load();
         started = true;
 
         if (Config.DEBUG) {
@@ -102,7 +102,7 @@
             return;
         }
         mContext.unregisterReceiver(this);
-        mInstaller.removeCompatibilityVersion(Config.COMPATIBILITY_VERSION);
+        mDataStore.delete();
         started = false;
 
         if (Config.DEBUG) {
@@ -111,7 +111,7 @@
     }
 
     long startPublicKeyDownload() {
-        long downloadId = download(mDataStore.getProperty(Config.PUBLIC_KEY_URL));
+        long downloadId = download(Config.URL_PUBLIC_KEY);
         if (downloadId != -1) {
             mDataStore.setPropertyLong(Config.PUBLIC_KEY_DOWNLOAD_ID, downloadId);
             mDataStore.store();
@@ -119,19 +119,31 @@
         return downloadId;
     }
 
-    long startMetadataDownload() {
-        long downloadId = download(mDataStore.getProperty(Config.METADATA_URL));
+    private long startMetadataDownload(CompatibilityVersion compatVersion) {
+        long downloadId = download(compatVersion.getMetadataUrl());
         if (downloadId != -1) {
-            mDataStore.setPropertyLong(Config.METADATA_DOWNLOAD_ID, downloadId);
+            mDataStore.setPropertyLong(compatVersion.getMetadataPropertyName(), downloadId);
             mDataStore.store();
         }
         return downloadId;
     }
 
-    long startContentDownload() {
-        long downloadId = download(mDataStore.getProperty(Config.CONTENT_URL));
+    @VisibleForTesting
+    void startMetadataDownload() {
+        for (CompatibilityVersion compatVersion : mCompatVersions) {
+            if (startMetadataDownload(compatVersion) == -1) {
+                Log.e(TAG, "Metadata download not started for " + compatVersion.getCompatVersion());
+            } else if (Config.DEBUG) {
+                Log.d(TAG, "Metadata download started for " + compatVersion.getCompatVersion());
+            }
+        }
+    }
+
+    @VisibleForTesting
+    long startContentDownload(CompatibilityVersion compatVersion) {
+        long downloadId = download(compatVersion.getContentUrl());
         if (downloadId != -1) {
-            mDataStore.setPropertyLong(Config.CONTENT_DOWNLOAD_ID, downloadId);
+            mDataStore.setPropertyLong(compatVersion.getContentPropertyName(), downloadId);
             mDataStore.store();
         }
         return downloadId;
@@ -145,25 +157,28 @@
             return;
         }
 
-        long completedId = intent.getLongExtra(DownloadManager.EXTRA_DOWNLOAD_ID, -1);
+        long completedId =
+                intent.getLongExtra(DownloadManager.EXTRA_DOWNLOAD_ID, /* defaultValue= */ -1);
         if (completedId == -1) {
             Log.e(TAG, "Invalid completed download Id");
             return;
         }
 
-        if (isPublicKeyDownloadId(completedId)) {
+        if (getPublicKeyDownloadId() == completedId) {
             handlePublicKeyDownloadCompleted(completedId);
             return;
         }
 
-        if (isMetadataDownloadId(completedId)) {
-            handleMetadataDownloadCompleted(completedId);
-            return;
-        }
+        for (CompatibilityVersion compatVersion : mCompatVersions) {
+            if (getMetadataDownloadId(compatVersion) == completedId) {
+                handleMetadataDownloadCompleted(compatVersion, completedId);
+                return;
+            }
 
-        if (isContentDownloadId(completedId)) {
-            handleContentDownloadCompleted(completedId);
-            return;
+            if (getContentDownloadId(compatVersion) == completedId) {
+                handleContentDownloadCompleted(compatVersion, completedId);
+                return;
+            }
         }
 
         Log.i(TAG, "Download id " + completedId + " is not recognized.");
@@ -189,35 +204,33 @@
             return;
         }
 
-        if (startMetadataDownload() == -1) {
-            Log.e(TAG, "Metadata download not started.");
-        } else if (Config.DEBUG) {
-            Log.d(TAG, "Metadata download started successfully.");
-        }
+        startMetadataDownload();
     }
 
-    private void handleMetadataDownloadCompleted(long downloadId) {
+    private void handleMetadataDownloadCompleted(
+            CompatibilityVersion compatVersion, long downloadId) {
         DownloadStatus status = mDownloadHelper.getDownloadStatus(downloadId);
         if (!status.isSuccessful()) {
             handleDownloadFailed(status);
             return;
         }
-        if (startContentDownload() == -1) {
-            Log.e(TAG, "Content download not started.");
+        if (startContentDownload(compatVersion) == -1) {
+            Log.e(TAG, "Content download failed for" + compatVersion.getCompatVersion());
         } else if (Config.DEBUG) {
-            Log.d(TAG, "Content download started successfully.");
+            Log.d(TAG, "Content download started for" + compatVersion.getCompatVersion());
         }
     }
 
-    private void handleContentDownloadCompleted(long downloadId) {
+    private void handleContentDownloadCompleted(
+            CompatibilityVersion compatVersion, long downloadId) {
         DownloadStatus status = mDownloadHelper.getDownloadStatus(downloadId);
         if (!status.isSuccessful()) {
             handleDownloadFailed(status);
             return;
         }
 
-        Uri contentUri = getContentDownloadUri();
-        Uri metadataUri = getMetadataDownloadUri();
+        Uri contentUri = getContentDownloadUri(compatVersion);
+        Uri metadataUri = getMetadataDownloadUri(compatVersion);
         if (contentUri == null || metadataUri == null) {
             Log.e(TAG, "Invalid URIs");
             return;
@@ -234,8 +247,7 @@
                 mLogger.logCTLogListUpdateFailedEvent(
                         CERTIFICATE_TRANSPARENCY_LOG_LIST_UPDATE_FAILED__FAILURE_REASON__FAILURE_SIGNATURE_NOT_FOUND,
                         mDataStore.getPropertyInt(
-                            Config.LOG_LIST_UPDATE_FAILURE_COUNT, /* defaultValue= */ 0)
-                );
+                                Config.LOG_LIST_UPDATE_FAILURE_COUNT, /* defaultValue= */ 0));
             }
         } catch (InvalidKeyException e) {
             if (updateFailureCount()) {
@@ -243,8 +255,7 @@
                 mLogger.logCTLogListUpdateFailedEvent(
                         CERTIFICATE_TRANSPARENCY_LOG_LIST_UPDATE_FAILED__FAILURE_REASON__FAILURE_SIGNATURE_VERIFICATION,
                         mDataStore.getPropertyInt(
-                            Config.LOG_LIST_UPDATE_FAILURE_COUNT, /* defaultValue= */ 0)
-                );
+                                Config.LOG_LIST_UPDATE_FAILURE_COUNT, /* defaultValue= */ 0));
             }
         } catch (IOException | GeneralSecurityException e) {
             Log.e(TAG, "Could not verify new log list", e);
@@ -258,32 +269,19 @@
                 mLogger.logCTLogListUpdateFailedEvent(
                         CERTIFICATE_TRANSPARENCY_LOG_LIST_UPDATE_FAILED__FAILURE_REASON__FAILURE_SIGNATURE_VERIFICATION,
                         mDataStore.getPropertyInt(
-                            Config.LOG_LIST_UPDATE_FAILURE_COUNT, /* defaultValue= */ 0));
+                                Config.LOG_LIST_UPDATE_FAILURE_COUNT, /* defaultValue= */ 0));
             }
             return;
         }
 
-        String version = null;
         try (InputStream inputStream = mContext.getContentResolver().openInputStream(contentUri)) {
-            version =
-                    new JSONObject(new String(inputStream.readAllBytes(), UTF_8))
-                            .getString("version");
-        } catch (JSONException | IOException e) {
-            Log.e(TAG, "Could not extract version from log list", e);
-            return;
-        }
-
-        try (InputStream inputStream = mContext.getContentResolver().openInputStream(contentUri)) {
-            success = mInstaller.install(Config.COMPATIBILITY_VERSION, inputStream, version);
+            success = compatVersion.install(inputStream);
         } catch (IOException e) {
             Log.e(TAG, "Could not install new content", e);
             return;
         }
 
         if (success) {
-            // Update information about the stored version on successful install.
-            mDataStore.setProperty(Config.VERSION, version);
-
             // Reset the number of consecutive log list failure updates back to zero.
             mDataStore.setPropertyInt(Config.LOG_LIST_UPDATE_FAILURE_COUNT, /* value= */ 0);
             mDataStore.store();
@@ -373,17 +371,19 @@
 
     @VisibleForTesting
     long getPublicKeyDownloadId() {
-        return mDataStore.getPropertyLong(Config.PUBLIC_KEY_DOWNLOAD_ID, -1);
+        return mDataStore.getPropertyLong(Config.PUBLIC_KEY_DOWNLOAD_ID, /* defaultValue= */ -1);
     }
 
     @VisibleForTesting
-    long getMetadataDownloadId() {
-        return mDataStore.getPropertyLong(Config.METADATA_DOWNLOAD_ID, -1);
+    long getMetadataDownloadId(CompatibilityVersion compatVersion) {
+        return mDataStore.getPropertyLong(
+                compatVersion.getMetadataPropertyName(), /* defaultValue */ -1);
     }
 
     @VisibleForTesting
-    long getContentDownloadId() {
-        return mDataStore.getPropertyLong(Config.CONTENT_DOWNLOAD_ID, -1);
+    long getContentDownloadId(CompatibilityVersion compatVersion) {
+        return mDataStore.getPropertyLong(
+                compatVersion.getContentPropertyName(), /* defaultValue= */ -1);
     }
 
     @VisibleForTesting
@@ -393,38 +393,27 @@
 
     @VisibleForTesting
     boolean hasMetadataDownloadId() {
-        return getMetadataDownloadId() != -1;
+        return mCompatVersions.stream()
+                .map(this::getMetadataDownloadId)
+                .anyMatch(downloadId -> downloadId != -1);
     }
 
     @VisibleForTesting
     boolean hasContentDownloadId() {
-        return getContentDownloadId() != -1;
-    }
-
-    @VisibleForTesting
-    boolean isPublicKeyDownloadId(long downloadId) {
-        return getPublicKeyDownloadId() == downloadId;
-    }
-
-    @VisibleForTesting
-    boolean isMetadataDownloadId(long downloadId) {
-        return getMetadataDownloadId() == downloadId;
-    }
-
-    @VisibleForTesting
-    boolean isContentDownloadId(long downloadId) {
-        return getContentDownloadId() == downloadId;
+        return mCompatVersions.stream()
+                .map(this::getContentDownloadId)
+                .anyMatch(downloadId -> downloadId != -1);
     }
 
     private Uri getPublicKeyDownloadUri() {
         return mDownloadHelper.getUri(getPublicKeyDownloadId());
     }
 
-    private Uri getMetadataDownloadUri() {
-        return mDownloadHelper.getUri(getMetadataDownloadId());
+    private Uri getMetadataDownloadUri(CompatibilityVersion compatVersion) {
+        return mDownloadHelper.getUri(getMetadataDownloadId(compatVersion));
     }
 
-    private Uri getContentDownloadUri() {
-        return mDownloadHelper.getUri(getContentDownloadId());
+    private Uri getContentDownloadUri(CompatibilityVersion compatVersion) {
+        return mDownloadHelper.getUri(getContentDownloadId(compatVersion));
     }
 }
diff --git a/networksecurity/service/src/com/android/server/net/ct/CertificateTransparencyInstaller.java b/networksecurity/service/src/com/android/server/net/ct/CertificateTransparencyInstaller.java
deleted file mode 100644
index 9970667..0000000
--- a/networksecurity/service/src/com/android/server/net/ct/CertificateTransparencyInstaller.java
+++ /dev/null
@@ -1,92 +0,0 @@
-/*
- * Copyright (C) 2024 The Android Open Source Project
- *
- * Licensed under the Apache License, Version 2.0 (the "License");
- * you may not use this file except in compliance with the License.
- * You may obtain a copy of the License at
- *
- *      http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing, software
- * distributed under the License is distributed on an "AS IS" BASIS,
- * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
- * See the License for the specific language governing permissions and
- * limitations under the License.
- */
-package com.android.server.net.ct;
-
-import android.util.Log;
-
-import java.io.File;
-import java.io.IOException;
-import java.io.InputStream;
-import java.util.HashMap;
-import java.util.Map;
-
-/** Installer of CT log lists. */
-public class CertificateTransparencyInstaller {
-
-    private static final String TAG = "CertificateTransparencyInstaller";
-
-    private final Map<String, CompatibilityVersion> mCompatVersions = new HashMap<>();
-
-    // The CT root directory.
-    private final File mRootDirectory;
-
-    public CertificateTransparencyInstaller(File rootDirectory) {
-        mRootDirectory = rootDirectory;
-    }
-
-    public CertificateTransparencyInstaller(String rootDirectoryPath) {
-        this(new File(rootDirectoryPath));
-    }
-
-    public CertificateTransparencyInstaller() {
-        this(Config.CT_ROOT_DIRECTORY_PATH);
-    }
-
-    void addCompatibilityVersion(String versionName) {
-        removeCompatibilityVersion(versionName);
-        CompatibilityVersion newCompatVersion =
-                new CompatibilityVersion(new File(mRootDirectory, versionName));
-        mCompatVersions.put(versionName, newCompatVersion);
-    }
-
-    void removeCompatibilityVersion(String versionName) {
-        CompatibilityVersion compatVersion = mCompatVersions.remove(versionName);
-        if (compatVersion != null && !compatVersion.delete()) {
-            Log.w(TAG, "Could not delete compatibility version directory.");
-        }
-    }
-
-    CompatibilityVersion getCompatibilityVersion(String versionName) {
-        return mCompatVersions.get(versionName);
-    }
-
-    /**
-     * Install a new log list to use during SCT verification.
-     *
-     * @param compatibilityVersion the compatibility version of the new log list
-     * @param newContent an input stream providing the log list
-     * @param version the minor version of the new log list
-     * @return true if the log list was installed successfully, false otherwise.
-     * @throws IOException if the list cannot be saved in the CT directory.
-     */
-    public boolean install(String compatibilityVersion, InputStream newContent, String version)
-            throws IOException {
-        CompatibilityVersion compatVersion = mCompatVersions.get(compatibilityVersion);
-        if (compatVersion == null) {
-            Log.e(TAG, "No compatibility version for " + compatibilityVersion);
-            return false;
-        }
-        // Ensure root directory exists and is readable.
-        DirectoryUtils.makeDir(mRootDirectory);
-
-        if (!compatVersion.install(newContent, version)) {
-            Log.e(TAG, "Failed to install logs version " + version);
-            return false;
-        }
-        Log.i(TAG, "New logs installed at " + compatVersion.getLogsDir());
-        return true;
-    }
-}
diff --git a/networksecurity/service/src/com/android/server/net/ct/CertificateTransparencyJob.java b/networksecurity/service/src/com/android/server/net/ct/CertificateTransparencyJob.java
index 9c92d14..a8acc60 100644
--- a/networksecurity/service/src/com/android/server/net/ct/CertificateTransparencyJob.java
+++ b/networksecurity/service/src/com/android/server/net/ct/CertificateTransparencyJob.java
@@ -36,7 +36,7 @@
     private static final String UPDATE_CONFIG_PERMISSION = "android.permission.UPDATE_CONFIG";
 
     private final Context mContext;
-    private final DataStore mDataStore;
+    private final CompatibilityVersion mCompatVersion;
     private final CertificateTransparencyDownloader mCertificateTransparencyDownloader;
     private final AlarmManager mAlarmManager;
     private final PendingIntent mPendingIntent;
@@ -45,12 +45,16 @@
 
     /** Creates a new {@link CertificateTransparencyJob} object. */
     public CertificateTransparencyJob(
-            Context context,
-            DataStore dataStore,
-            CertificateTransparencyDownloader certificateTransparencyDownloader) {
+            Context context, CertificateTransparencyDownloader certificateTransparencyDownloader) {
         mContext = context;
-        mDataStore = dataStore;
+        mCompatVersion =
+                new CompatibilityVersion(
+                        Config.COMPATIBILITY_VERSION,
+                        Config.URL_SIGNATURE,
+                        Config.URL_LOG_LIST,
+                        Config.CT_ROOT_DIRECTORY_PATH);
         mCertificateTransparencyDownloader = certificateTransparencyDownloader;
+        mCertificateTransparencyDownloader.addCompatibilityVersion(mCompatVersion);
         mAlarmManager = context.getSystemService(AlarmManager.class);
         mPendingIntent =
                 PendingIntent.getBroadcast(
@@ -80,6 +84,7 @@
         mContext.unregisterReceiver(this);
         mAlarmManager.cancel(mPendingIntent);
         mCertificateTransparencyDownloader.stop();
+        mCompatVersion.delete();
         mDependenciesReady = false;
 
         if (Config.DEBUG) {
@@ -102,16 +107,10 @@
             Log.d(TAG, "Starting CT daily job.");
         }
         if (!mDependenciesReady) {
-            mDataStore.load();
             mCertificateTransparencyDownloader.start();
             mDependenciesReady = true;
         }
 
-        mDataStore.setProperty(Config.CONTENT_URL, Config.URL_LOG_LIST);
-        mDataStore.setProperty(Config.METADATA_URL, Config.URL_SIGNATURE);
-        mDataStore.setProperty(Config.PUBLIC_KEY_URL, Config.URL_PUBLIC_KEY);
-        mDataStore.store();
-
         if (mCertificateTransparencyDownloader.startPublicKeyDownload() == -1) {
             Log.e(TAG, "Public key download not started.");
         } else if (Config.DEBUG) {
diff --git a/networksecurity/service/src/com/android/server/net/ct/CertificateTransparencyService.java b/networksecurity/service/src/com/android/server/net/ct/CertificateTransparencyService.java
index eb24567..ed98056 100644
--- a/networksecurity/service/src/com/android/server/net/ct/CertificateTransparencyService.java
+++ b/networksecurity/service/src/com/android/server/net/ct/CertificateTransparencyService.java
@@ -61,10 +61,8 @@
                         dataStore,
                         downloadHelper,
                         signatureVerifier,
-                        new CertificateTransparencyInstaller(),
                         new CertificateTransparencyLoggerImpl());
-        mCertificateTransparencyJob =
-                new CertificateTransparencyJob(context, dataStore, downloader);
+        mCertificateTransparencyJob = new CertificateTransparencyJob(context, downloader);
     }
 
     /**
diff --git a/networksecurity/service/src/com/android/server/net/ct/CompatibilityVersion.java b/networksecurity/service/src/com/android/server/net/ct/CompatibilityVersion.java
index 27488b5..fdeb746 100644
--- a/networksecurity/service/src/com/android/server/net/ct/CompatibilityVersion.java
+++ b/networksecurity/service/src/com/android/server/net/ct/CompatibilityVersion.java
@@ -15,58 +15,92 @@
  */
 package com.android.server.net.ct;
 
+import static java.nio.charset.StandardCharsets.UTF_8;
+
+import android.annotation.RequiresApi;
+import android.os.Build;
 import android.system.ErrnoException;
 import android.system.Os;
+import android.util.Log;
 
+import org.json.JSONException;
+import org.json.JSONObject;
+
+import java.io.ByteArrayInputStream;
 import java.io.File;
 import java.io.IOException;
 import java.io.InputStream;
 import java.nio.file.Files;
 
 /** Represents a compatibility version directory. */
+@RequiresApi(Build.VERSION_CODES.VANILLA_ICE_CREAM)
 class CompatibilityVersion {
 
+    private static final String TAG = "CompatibilityVersion";
+
     static final String LOGS_DIR_PREFIX = "logs-";
     static final String LOGS_LIST_FILE_NAME = "log_list.json";
+    static final String CURRENT_LOGS_DIR_SYMLINK_NAME = "current";
 
-    private static final String CURRENT_LOGS_DIR_SYMLINK_NAME = "current";
+    private final String mCompatVersion;
 
-    private final File mRootDirectory;
+    private final String mMetadataUrl;
+    private final String mContentUrl;
+    private final File mVersionDirectory;
     private final File mCurrentLogsDirSymlink;
 
-    private File mCurrentLogsDir = null;
+    CompatibilityVersion(
+            String compatVersion, String metadataUrl, String contentUrl, File rootDirectory) {
+        mCompatVersion = compatVersion;
+        mMetadataUrl = metadataUrl;
+        mContentUrl = contentUrl;
+        mVersionDirectory = new File(rootDirectory, compatVersion);
+        mCurrentLogsDirSymlink = new File(mVersionDirectory, CURRENT_LOGS_DIR_SYMLINK_NAME);
+    }
 
-    CompatibilityVersion(File rootDirectory) {
-        mRootDirectory = rootDirectory;
-        mCurrentLogsDirSymlink = new File(mRootDirectory, CURRENT_LOGS_DIR_SYMLINK_NAME);
+    CompatibilityVersion(
+            String compatVersion, String metadataUrl, String contentUrl, String rootDirectoryPath) {
+        this(compatVersion, metadataUrl, contentUrl, new File(rootDirectoryPath));
     }
 
     /**
      * Installs a log list within this compatibility version directory.
      *
      * @param newContent an input stream providing the log list
-     * @param version the version number of the log list
      * @return true if the log list was installed successfully, false otherwise.
      * @throws IOException if the list cannot be saved in the CT directory.
      */
-    boolean install(InputStream newContent, String version) throws IOException {
-        // To support atomically replacing the old configuration directory with the new there's a
-        // bunch of steps. We create a new directory with the logs and then do an atomic update of
-        // the current symlink to point to the new directory.
-        // 1. Ensure that the root directory exists and is readable.
-        DirectoryUtils.makeDir(mRootDirectory);
+    boolean install(InputStream newContent) throws IOException {
+        String content = new String(newContent.readAllBytes(), UTF_8);
+        try {
+            return install(
+                    new ByteArrayInputStream(content.getBytes()),
+                    new JSONObject(content).getString("version"));
+        } catch (JSONException e) {
+            Log.e(TAG, "invalid log list format", e);
+            return false;
+        }
+    }
 
-        File newLogsDir = new File(mRootDirectory, LOGS_DIR_PREFIX + version);
+    private boolean install(InputStream newContent, String version) throws IOException {
+        // To support atomically replacing the old configuration directory with the new
+        // there's a bunch of steps. We create a new directory with the logs and then do
+        // an atomic update of the current symlink to point to the new directory.
+        // 1. Ensure the path to the root directory exists and is readable.
+        DirectoryUtils.makeDir(mVersionDirectory);
+
+        File newLogsDir = new File(mVersionDirectory, LOGS_DIR_PREFIX + version);
         // 2. Handle the corner case where the new directory already exists.
         if (newLogsDir.exists()) {
-            // If the symlink has already been updated then the update died between steps 6 and 7
-            // and so we cannot delete the directory since it is in use.
+            // If the symlink has already been updated then the update died between steps 6
+            // and 7 and so we cannot delete the directory since it is in use.
             if (newLogsDir.getCanonicalPath().equals(mCurrentLogsDirSymlink.getCanonicalPath())) {
+                Log.i(TAG, newLogsDir + " already exists, skipping install.");
                 deleteOldLogDirectories();
                 return false;
             }
-            // If the symlink has not been updated then the previous installation failed and this is
-            // a re-attempt. Clean-up leftover files and try again.
+            // If the symlink has not been updated then the previous installation failed and
+            // this is a re-attempt. Clean-up leftover files and try again.
             DirectoryUtils.removeDir(newLogsDir);
         }
         try {
@@ -80,8 +114,8 @@
             }
             DirectoryUtils.setWorldReadable(logListFile);
 
-            // 5. Create temp symlink. We rename this to the target symlink to get an atomic update.
-            File tempSymlink = new File(mRootDirectory, "new_symlink");
+            // 5. Create temp symlink. We rename to the target symlink for an atomic update.
+            File tempSymlink = new File(mVersionDirectory, "new_symlink");
             try {
                 Os.symlink(newLogsDir.getCanonicalPath(), tempSymlink.getCanonicalPath());
             } catch (ErrnoException e) {
@@ -95,17 +129,33 @@
             throw e;
         }
         // 7. Cleanup
-        mCurrentLogsDir = newLogsDir;
+        Log.i(TAG, "New logs installed at " + newLogsDir);
         deleteOldLogDirectories();
         return true;
     }
 
-    File getRootDir() {
-        return mRootDirectory;
+    String getCompatVersion() {
+        return mCompatVersion;
     }
 
-    File getLogsDir() {
-        return mCurrentLogsDir;
+    String getMetadataUrl() {
+        return mMetadataUrl;
+    }
+
+    String getMetadataPropertyName() {
+        return mCompatVersion + "_" + Config.METADATA_DOWNLOAD_ID;
+    }
+
+    String getContentUrl() {
+        return mContentUrl;
+    }
+
+    String getContentPropertyName() {
+        return mCompatVersion + "_" + Config.CONTENT_DOWNLOAD_ID;
+    }
+
+    File getVersionDir() {
+        return mVersionDirectory;
     }
 
     File getLogsDirSymlink() {
@@ -113,19 +163,21 @@
     }
 
     File getLogsFile() {
-        return new File(mCurrentLogsDir, LOGS_LIST_FILE_NAME);
+        return new File(mCurrentLogsDirSymlink, LOGS_LIST_FILE_NAME);
     }
 
-    boolean delete() {
-        return DirectoryUtils.removeDir(mRootDirectory);
+    void delete() {
+        if (!DirectoryUtils.removeDir(mVersionDirectory)) {
+            Log.w(TAG, "Could not delete compatibility version directory " + mVersionDirectory);
+        }
     }
 
     private void deleteOldLogDirectories() throws IOException {
-        if (!mRootDirectory.exists()) {
+        if (!mVersionDirectory.exists()) {
             return;
         }
         File currentTarget = mCurrentLogsDirSymlink.getCanonicalFile();
-        for (File file : mRootDirectory.listFiles()) {
+        for (File file : mVersionDirectory.listFiles()) {
             if (!currentTarget.equals(file.getCanonicalFile())
                     && file.getName().startsWith(LOGS_DIR_PREFIX)) {
                 DirectoryUtils.removeDir(file);
diff --git a/networksecurity/service/src/com/android/server/net/ct/Config.java b/networksecurity/service/src/com/android/server/net/ct/Config.java
index aafee60..592bc4e 100644
--- a/networksecurity/service/src/com/android/server/net/ct/Config.java
+++ b/networksecurity/service/src/com/android/server/net/ct/Config.java
@@ -48,11 +48,8 @@
 
     // properties
     static final String VERSION = "version";
-    static final String CONTENT_URL = "content_url";
     static final String CONTENT_DOWNLOAD_ID = "content_download_id";
-    static final String METADATA_URL = "metadata_url";
     static final String METADATA_DOWNLOAD_ID = "metadata_download_id";
-    static final String PUBLIC_KEY_URL = "public_key_url";
     static final String PUBLIC_KEY_DOWNLOAD_ID = "public_key_download_id";
     static final String LOG_LIST_UPDATE_FAILURE_COUNT = "log_list_update_failure_count";
 
diff --git a/networksecurity/service/src/com/android/server/net/ct/DataStore.java b/networksecurity/service/src/com/android/server/net/ct/DataStore.java
index 3779269..8180316 100644
--- a/networksecurity/service/src/com/android/server/net/ct/DataStore.java
+++ b/networksecurity/service/src/com/android/server/net/ct/DataStore.java
@@ -57,6 +57,11 @@
         }
     }
 
+    boolean delete() {
+        clear();
+        return mPropertyFile.delete();
+    }
+
     long getPropertyLong(String key, long defaultValue) {
         return Optional.ofNullable(getProperty(key)).map(Long::parseLong).orElse(defaultValue);
     }
diff --git a/networksecurity/service/src/com/android/server/net/ct/DirectoryUtils.java b/networksecurity/service/src/com/android/server/net/ct/DirectoryUtils.java
index ba42a82..54e277a 100644
--- a/networksecurity/service/src/com/android/server/net/ct/DirectoryUtils.java
+++ b/networksecurity/service/src/com/android/server/net/ct/DirectoryUtils.java
@@ -25,7 +25,7 @@
 class DirectoryUtils {
 
     static void makeDir(File dir) throws IOException {
-        dir.mkdir();
+        dir.mkdirs();
         if (!dir.isDirectory()) {
             throw new IOException("Unable to make directory " + dir.getCanonicalPath());
         }
diff --git a/networksecurity/tests/unit/src/com/android/server/net/ct/CertificateTransparencyDownloaderTest.java b/networksecurity/tests/unit/src/com/android/server/net/ct/CertificateTransparencyDownloaderTest.java
index 25f0dc1..5552689 100644
--- a/networksecurity/tests/unit/src/com/android/server/net/ct/CertificateTransparencyDownloaderTest.java
+++ b/networksecurity/tests/unit/src/com/android/server/net/ct/CertificateTransparencyDownloaderTest.java
@@ -13,6 +13,7 @@
  * See the License for the specific language governing permissions and
  * limitations under the License.
  */
+
 package com.android.server.net.ct;
 
 import static com.android.server.net.ct.CertificateTransparencyStatsLog.CERTIFICATE_TRANSPARENCY_LOG_LIST_UPDATE_FAILED__FAILURE_REASON__FAILURE_NO_DISK_SPACE;
@@ -24,7 +25,6 @@
 
 import static org.mockito.ArgumentMatchers.any;
 import static org.mockito.ArgumentMatchers.anyInt;
-import static org.mockito.ArgumentMatchers.anyString;
 import static org.mockito.ArgumentMatchers.eq;
 import static org.mockito.Mockito.never;
 import static org.mockito.Mockito.times;
@@ -73,15 +73,14 @@
 public class CertificateTransparencyDownloaderTest {
 
     @Mock private DownloadManager mDownloadManager;
-    @Mock private CertificateTransparencyInstaller mCertificateTransparencyInstaller;
     @Mock private CertificateTransparencyLogger mLogger;
 
     private PrivateKey mPrivateKey;
     private PublicKey mPublicKey;
     private Context mContext;
-    private File mTempFile;
     private DataStore mDataStore;
     private SignatureVerifier mSignatureVerifier;
+    private CompatibilityVersion mCompatVersion;
     private CertificateTransparencyDownloader mCertificateTransparencyDownloader;
 
     private long mNextDownloadId = 666;
@@ -95,8 +94,7 @@
         mPublicKey = keyPair.getPublic();
 
         mContext = InstrumentationRegistry.getInstrumentation().getContext();
-        mTempFile = File.createTempFile("datastore-test", ".properties");
-        mDataStore = new DataStore(mTempFile);
+        mDataStore = new DataStore(File.createTempFile("datastore-test", ".properties"));
         mSignatureVerifier = new SignatureVerifier(mContext);
         mCertificateTransparencyDownloader =
                 new CertificateTransparencyDownloader(
@@ -104,56 +102,64 @@
                         mDataStore,
                         new DownloadHelper(mDownloadManager),
                         mSignatureVerifier,
-                        mCertificateTransparencyInstaller,
                         mLogger);
+        mCompatVersion =
+                new CompatibilityVersion(
+                        /* compatVersion= */ "v666",
+                        Config.URL_SIGNATURE,
+                        Config.URL_LOG_LIST,
+                        mContext.getFilesDir());
 
-        prepareDataStore();
         prepareDownloadManager();
+        mCertificateTransparencyDownloader.addCompatibilityVersion(mCompatVersion);
+        mCertificateTransparencyDownloader.start();
     }
 
     @After
     public void tearDown() {
-        mTempFile.delete();
         mSignatureVerifier.resetPublicKey();
+        mCertificateTransparencyDownloader.stop();
+        mCompatVersion.delete();
     }
 
     @Test
     public void testDownloader_startPublicKeyDownload() {
         assertThat(mCertificateTransparencyDownloader.hasPublicKeyDownloadId()).isFalse();
+
         long downloadId = mCertificateTransparencyDownloader.startPublicKeyDownload();
 
         assertThat(mCertificateTransparencyDownloader.hasPublicKeyDownloadId()).isTrue();
-        assertThat(mCertificateTransparencyDownloader.isPublicKeyDownloadId(downloadId)).isTrue();
+        assertThat(mCertificateTransparencyDownloader.getPublicKeyDownloadId())
+                .isEqualTo(downloadId);
     }
 
     @Test
     public void testDownloader_startMetadataDownload() {
         assertThat(mCertificateTransparencyDownloader.hasMetadataDownloadId()).isFalse();
-        long downloadId = mCertificateTransparencyDownloader.startMetadataDownload();
+
+        mCertificateTransparencyDownloader.startMetadataDownload();
 
         assertThat(mCertificateTransparencyDownloader.hasMetadataDownloadId()).isTrue();
-        assertThat(mCertificateTransparencyDownloader.isMetadataDownloadId(downloadId)).isTrue();
     }
 
     @Test
     public void testDownloader_startContentDownload() {
         assertThat(mCertificateTransparencyDownloader.hasContentDownloadId()).isFalse();
-        long downloadId = mCertificateTransparencyDownloader.startContentDownload();
+
+        mCertificateTransparencyDownloader.startContentDownload(mCompatVersion);
 
         assertThat(mCertificateTransparencyDownloader.hasContentDownloadId()).isTrue();
-        assertThat(mCertificateTransparencyDownloader.isContentDownloadId(downloadId)).isTrue();
     }
 
     @Test
     public void testDownloader_publicKeyDownloadSuccess_updatePublicKey_startMetadataDownload()
             throws Exception {
-        long publicKeyId = mCertificateTransparencyDownloader.startPublicKeyDownload();
-        setSuccessfulDownload(publicKeyId, writePublicKeyToFile(mPublicKey));
+        mCertificateTransparencyDownloader.startPublicKeyDownload();
 
         assertThat(mSignatureVerifier.getPublicKey()).isEmpty();
         assertThat(mCertificateTransparencyDownloader.hasMetadataDownloadId()).isFalse();
         mCertificateTransparencyDownloader.onReceive(
-                mContext, makeDownloadCompleteIntent(publicKeyId));
+                mContext, makePublicKeyDownloadCompleteIntent(writePublicKeyToFile(mPublicKey)));
 
         assertThat(mSignatureVerifier.getPublicKey()).hasValue(mPublicKey);
         assertThat(mCertificateTransparencyDownloader.hasMetadataDownloadId()).isTrue();
@@ -163,14 +169,14 @@
     public void
             testDownloader_publicKeyDownloadSuccess_updatePublicKeyFail_doNotStartMetadataDownload()
                     throws Exception {
-        long publicKeyId = mCertificateTransparencyDownloader.startPublicKeyDownload();
-        setSuccessfulDownload(
-                publicKeyId, writeToFile("i_am_not_a_base64_encoded_public_key".getBytes()));
+        mCertificateTransparencyDownloader.startPublicKeyDownload();
 
         assertThat(mSignatureVerifier.getPublicKey()).isEmpty();
         assertThat(mCertificateTransparencyDownloader.hasMetadataDownloadId()).isFalse();
         mCertificateTransparencyDownloader.onReceive(
-                mContext, makeDownloadCompleteIntent(publicKeyId));
+                mContext,
+                makePublicKeyDownloadCompleteIntent(
+                        writeToFile("i_am_not_a_base64_encoded_public_key".getBytes())));
 
         assertThat(mSignatureVerifier.getPublicKey()).isEmpty();
         assertThat(mCertificateTransparencyDownloader.hasMetadataDownloadId()).isFalse();
@@ -178,17 +184,15 @@
 
     @Test
     public void testDownloader_publicKeyDownloadFail_doNotUpdatePublicKey() throws Exception {
-        long publicKeyId = mCertificateTransparencyDownloader.startPublicKeyDownload();
-        setFailedDownload(
-                publicKeyId, // Failure cases where we give up on the download.
-                DownloadManager.ERROR_INSUFFICIENT_SPACE,
-                DownloadManager.ERROR_HTTP_DATA_ERROR);
-        Intent downloadCompleteIntent = makeDownloadCompleteIntent(publicKeyId);
+        mCertificateTransparencyDownloader.startPublicKeyDownload();
 
         assertThat(mSignatureVerifier.getPublicKey()).isEmpty();
         assertThat(mCertificateTransparencyDownloader.hasMetadataDownloadId()).isFalse();
-        mCertificateTransparencyDownloader.onReceive(mContext, downloadCompleteIntent);
-        mCertificateTransparencyDownloader.onReceive(mContext, downloadCompleteIntent);
+        mCertificateTransparencyDownloader.onReceive(
+                mContext,
+                makePublicKeyDownloadFailedIntent(DownloadManager.ERROR_INSUFFICIENT_SPACE));
+        mCertificateTransparencyDownloader.onReceive(
+                mContext, makePublicKeyDownloadFailedIntent(DownloadManager.ERROR_HTTP_DATA_ERROR));
 
         assertThat(mSignatureVerifier.getPublicKey()).isEmpty();
         assertThat(mCertificateTransparencyDownloader.hasMetadataDownloadId()).isFalse();
@@ -196,225 +200,202 @@
 
     @Test
     public void testDownloader_publicKeyDownloadFail_failureThresholdExceeded_logsFailure()
-                throws Exception {
-        long publicKeyId = mCertificateTransparencyDownloader.startPublicKeyDownload();
+            throws Exception {
+        mCertificateTransparencyDownloader.startPublicKeyDownload();
         // Set the failure count to just below the threshold
-        mDataStore.setPropertyInt(Config.LOG_LIST_UPDATE_FAILURE_COUNT,
-                Config.LOG_LIST_UPDATE_FAILURE_THRESHOLD - 1);
-        setFailedDownload(
-                publicKeyId, // Failure cases where we give up on the download.
-                DownloadManager.ERROR_INSUFFICIENT_SPACE,
-                DownloadManager.ERROR_HTTP_DATA_ERROR);
-        Intent downloadCompleteIntent = makeDownloadCompleteIntent(publicKeyId);
+        mDataStore.setPropertyInt(
+                Config.LOG_LIST_UPDATE_FAILURE_COUNT, Config.LOG_LIST_UPDATE_FAILURE_THRESHOLD - 1);
 
-        mCertificateTransparencyDownloader.onReceive(mContext, downloadCompleteIntent);
+        mCertificateTransparencyDownloader.onReceive(
+                mContext,
+                makePublicKeyDownloadFailedIntent(DownloadManager.ERROR_INSUFFICIENT_SPACE));
 
-        assertThat(mDataStore.getPropertyInt(
-                Config.LOG_LIST_UPDATE_FAILURE_COUNT, /* defaultValue= */ 0))
-                        .isEqualTo(Config.LOG_LIST_UPDATE_FAILURE_THRESHOLD);
-        verify(mLogger, times(1)).logCTLogListUpdateFailedEvent(
-                CERTIFICATE_TRANSPARENCY_LOG_LIST_UPDATE_FAILED__FAILURE_REASON__FAILURE_NO_DISK_SPACE,
-                Config.LOG_LIST_UPDATE_FAILURE_THRESHOLD
-        );
+        assertThat(
+                        mDataStore.getPropertyInt(
+                                Config.LOG_LIST_UPDATE_FAILURE_COUNT, /* defaultValue= */ 0))
+                .isEqualTo(Config.LOG_LIST_UPDATE_FAILURE_THRESHOLD);
+        verify(mLogger, times(1))
+                .logCTLogListUpdateFailedEvent(
+                        CERTIFICATE_TRANSPARENCY_LOG_LIST_UPDATE_FAILED__FAILURE_REASON__FAILURE_NO_DISK_SPACE,
+                        Config.LOG_LIST_UPDATE_FAILURE_THRESHOLD);
     }
 
     @Test
     public void testDownloader_publicKeyDownloadFail_failureThresholdNotMet_doesNotLog()
-                throws Exception {
-        long publicKeyId = mCertificateTransparencyDownloader.startPublicKeyDownload();
+            throws Exception {
+        mCertificateTransparencyDownloader.startPublicKeyDownload();
         // Set the failure count to well below the threshold
         mDataStore.setPropertyInt(Config.LOG_LIST_UPDATE_FAILURE_COUNT, 0);
-        setFailedDownload(
-                publicKeyId, // Failure cases where we give up on the download.
-                DownloadManager.ERROR_INSUFFICIENT_SPACE,
-                DownloadManager.ERROR_HTTP_DATA_ERROR);
-        Intent downloadCompleteIntent = makeDownloadCompleteIntent(publicKeyId);
 
-        mCertificateTransparencyDownloader.onReceive(mContext, downloadCompleteIntent);
+        mCertificateTransparencyDownloader.onReceive(
+                mContext, makePublicKeyDownloadFailedIntent(DownloadManager.ERROR_HTTP_DATA_ERROR));
 
-        assertThat(mDataStore.getPropertyInt(
-                Config.LOG_LIST_UPDATE_FAILURE_COUNT, /* defaultValue= */ 0))
-                        .isEqualTo(1);
+        assertThat(
+                        mDataStore.getPropertyInt(
+                                Config.LOG_LIST_UPDATE_FAILURE_COUNT, /* defaultValue= */ 0))
+                .isEqualTo(1);
         verify(mLogger, never()).logCTLogListUpdateFailedEvent(anyInt(), anyInt());
     }
 
     @Test
     public void testDownloader_metadataDownloadSuccess_startContentDownload() {
-        long metadataId = mCertificateTransparencyDownloader.startMetadataDownload();
-        setSuccessfulDownload(metadataId, new File("log_list.sig"));
+        mCertificateTransparencyDownloader.startMetadataDownload();
 
         assertThat(mCertificateTransparencyDownloader.hasContentDownloadId()).isFalse();
         mCertificateTransparencyDownloader.onReceive(
-                mContext, makeDownloadCompleteIntent(metadataId));
+                mContext,
+                makeMetadataDownloadCompleteIntent(mCompatVersion, new File("log_list.sig")));
 
         assertThat(mCertificateTransparencyDownloader.hasContentDownloadId()).isTrue();
     }
 
     @Test
     public void testDownloader_metadataDownloadFail_doNotStartContentDownload() {
-        long metadataId = mCertificateTransparencyDownloader.startMetadataDownload();
-        setFailedDownload(
-                metadataId,
-                // Failure cases where we give up on the download.
-                DownloadManager.ERROR_INSUFFICIENT_SPACE,
-                DownloadManager.ERROR_HTTP_DATA_ERROR);
-        Intent downloadCompleteIntent = makeDownloadCompleteIntent(metadataId);
+        mCertificateTransparencyDownloader.startMetadataDownload();
 
         assertThat(mCertificateTransparencyDownloader.hasContentDownloadId()).isFalse();
-        mCertificateTransparencyDownloader.onReceive(mContext, downloadCompleteIntent);
-        mCertificateTransparencyDownloader.onReceive(mContext, downloadCompleteIntent);
+        mCertificateTransparencyDownloader.onReceive(
+                mContext,
+                makeMetadataDownloadFailedIntent(
+                        mCompatVersion, DownloadManager.ERROR_INSUFFICIENT_SPACE));
+        mCertificateTransparencyDownloader.onReceive(
+                mContext,
+                makeMetadataDownloadFailedIntent(
+                        mCompatVersion, DownloadManager.ERROR_HTTP_DATA_ERROR));
 
         assertThat(mCertificateTransparencyDownloader.hasContentDownloadId()).isFalse();
     }
 
     @Test
     public void testDownloader_metadataDownloadFail_failureThresholdExceeded_logsFailure()
-                throws Exception {
-        long metadataId = mCertificateTransparencyDownloader.startMetadataDownload();
+            throws Exception {
+        mCertificateTransparencyDownloader.startMetadataDownload();
         // Set the failure count to just below the threshold
-        mDataStore.setPropertyInt(Config.LOG_LIST_UPDATE_FAILURE_COUNT,
-                Config.LOG_LIST_UPDATE_FAILURE_THRESHOLD - 1);
-        setFailedDownload(
-                metadataId,
-                // Failure cases where we give up on the download.
-                DownloadManager.ERROR_INSUFFICIENT_SPACE,
-                DownloadManager.ERROR_HTTP_DATA_ERROR);
-        Intent downloadCompleteIntent = makeDownloadCompleteIntent(metadataId);
+        mDataStore.setPropertyInt(
+                Config.LOG_LIST_UPDATE_FAILURE_COUNT, Config.LOG_LIST_UPDATE_FAILURE_THRESHOLD - 1);
 
-        mCertificateTransparencyDownloader.onReceive(mContext, downloadCompleteIntent);
+        mCertificateTransparencyDownloader.onReceive(
+                mContext,
+                makeMetadataDownloadFailedIntent(
+                        mCompatVersion, DownloadManager.ERROR_INSUFFICIENT_SPACE));
 
-        assertThat(mDataStore.getPropertyInt(
-                Config.LOG_LIST_UPDATE_FAILURE_COUNT, /* defaultValue= */ 0))
-                        .isEqualTo(Config.LOG_LIST_UPDATE_FAILURE_THRESHOLD);
-        verify(mLogger, times(1)).logCTLogListUpdateFailedEvent(
-                CERTIFICATE_TRANSPARENCY_LOG_LIST_UPDATE_FAILED__FAILURE_REASON__FAILURE_NO_DISK_SPACE,
-                Config.LOG_LIST_UPDATE_FAILURE_THRESHOLD
-        );
+        assertThat(
+                        mDataStore.getPropertyInt(
+                                Config.LOG_LIST_UPDATE_FAILURE_COUNT, /* defaultValue= */ 0))
+                .isEqualTo(Config.LOG_LIST_UPDATE_FAILURE_THRESHOLD);
+        verify(mLogger, times(1))
+                .logCTLogListUpdateFailedEvent(
+                        CERTIFICATE_TRANSPARENCY_LOG_LIST_UPDATE_FAILED__FAILURE_REASON__FAILURE_NO_DISK_SPACE,
+                        Config.LOG_LIST_UPDATE_FAILURE_THRESHOLD);
     }
 
     @Test
     public void testDownloader_metadataDownloadFail_failureThresholdNotMet_doesNotLog()
-                throws Exception {
-        long metadataId = mCertificateTransparencyDownloader.startMetadataDownload();
+            throws Exception {
+        mCertificateTransparencyDownloader.startMetadataDownload();
         // Set the failure count to well below the threshold
         mDataStore.setPropertyInt(Config.LOG_LIST_UPDATE_FAILURE_COUNT, 0);
-        setFailedDownload(
-                metadataId,
-                // Failure cases where we give up on the download.
-                DownloadManager.ERROR_INSUFFICIENT_SPACE,
-                DownloadManager.ERROR_HTTP_DATA_ERROR);
-        Intent downloadCompleteIntent = makeDownloadCompleteIntent(metadataId);
 
-        mCertificateTransparencyDownloader.onReceive(mContext, downloadCompleteIntent);
+        mCertificateTransparencyDownloader.onReceive(
+                mContext,
+                makeMetadataDownloadFailedIntent(
+                        mCompatVersion, DownloadManager.ERROR_INSUFFICIENT_SPACE));
 
-        assertThat(mDataStore.getPropertyInt(
-                Config.LOG_LIST_UPDATE_FAILURE_COUNT, /* defaultValue= */ 0))
-                        .isEqualTo(1);
+        assertThat(
+                        mDataStore.getPropertyInt(
+                                Config.LOG_LIST_UPDATE_FAILURE_COUNT, /* defaultValue= */ 0))
+                .isEqualTo(1);
         verify(mLogger, never()).logCTLogListUpdateFailedEvent(anyInt(), anyInt());
     }
 
     @Test
-    public void testDownloader_contentDownloadSuccess_installSuccess_updateDataStore()
-            throws Exception {
+    public void testDownloader_contentDownloadSuccess_installSuccess() throws Exception {
         String newVersion = "456";
         File logListFile = makeLogListFile(newVersion);
         File metadataFile = sign(logListFile);
         mSignatureVerifier.setPublicKey(mPublicKey);
-        long metadataId = mCertificateTransparencyDownloader.startMetadataDownload();
-        setSuccessfulDownload(metadataId, metadataFile);
-        long contentId = mCertificateTransparencyDownloader.startContentDownload();
-        setSuccessfulDownload(contentId, logListFile);
-        when(mCertificateTransparencyInstaller.install(
-                        eq(Config.COMPATIBILITY_VERSION), any(), anyString()))
-                .thenReturn(true);
+        mCertificateTransparencyDownloader.startMetadataDownload();
 
         assertNoVersionIsInstalled();
         mCertificateTransparencyDownloader.onReceive(
-                mContext, makeDownloadCompleteIntent(contentId));
+                mContext, makeMetadataDownloadCompleteIntent(mCompatVersion, metadataFile));
+        mCertificateTransparencyDownloader.onReceive(
+                mContext, makeContentDownloadCompleteIntent(mCompatVersion, logListFile));
 
         assertInstallSuccessful(newVersion);
     }
 
     @Test
     public void testDownloader_contentDownloadFail_doNotInstall() throws Exception {
-        long contentId = mCertificateTransparencyDownloader.startContentDownload();
-        setFailedDownload(
-                contentId,
-                // Failure cases where we give up on the download.
-                DownloadManager.ERROR_INSUFFICIENT_SPACE,
-                DownloadManager.ERROR_HTTP_DATA_ERROR);
-        Intent downloadCompleteIntent = makeDownloadCompleteIntent(contentId);
+        mCertificateTransparencyDownloader.startContentDownload(mCompatVersion);
 
-        mCertificateTransparencyDownloader.onReceive(mContext, downloadCompleteIntent);
-        mCertificateTransparencyDownloader.onReceive(mContext, downloadCompleteIntent);
+        mCertificateTransparencyDownloader.onReceive(
+                mContext,
+                makeContentDownloadFailedIntent(
+                        mCompatVersion, DownloadManager.ERROR_INSUFFICIENT_SPACE));
+        mCertificateTransparencyDownloader.onReceive(
+                mContext,
+                makeContentDownloadFailedIntent(
+                        mCompatVersion, DownloadManager.ERROR_HTTP_DATA_ERROR));
 
-        verify(mCertificateTransparencyInstaller, never()).install(any(), any(), any());
         assertNoVersionIsInstalled();
     }
 
     @Test
     public void testDownloader_contentDownloadFail_failureThresholdExceeded_logsFailure()
-                throws Exception {
-        long contentId = mCertificateTransparencyDownloader.startContentDownload();
+            throws Exception {
+        mCertificateTransparencyDownloader.startContentDownload(mCompatVersion);
         // Set the failure count to just below the threshold
-        mDataStore.setPropertyInt(Config.LOG_LIST_UPDATE_FAILURE_COUNT,
-                Config.LOG_LIST_UPDATE_FAILURE_THRESHOLD - 1);
-        setFailedDownload(
-                contentId,
-                // Failure cases where we give up on the download.
-                DownloadManager.ERROR_INSUFFICIENT_SPACE,
-                DownloadManager.ERROR_HTTP_DATA_ERROR);
-        Intent downloadCompleteIntent = makeDownloadCompleteIntent(contentId);
+        mDataStore.setPropertyInt(
+                Config.LOG_LIST_UPDATE_FAILURE_COUNT, Config.LOG_LIST_UPDATE_FAILURE_THRESHOLD - 1);
 
-        mCertificateTransparencyDownloader.onReceive(mContext, downloadCompleteIntent);
+        mCertificateTransparencyDownloader.onReceive(
+                mContext,
+                makeContentDownloadFailedIntent(
+                        mCompatVersion, DownloadManager.ERROR_INSUFFICIENT_SPACE));
 
-        assertThat(mDataStore.getPropertyInt(
-                Config.LOG_LIST_UPDATE_FAILURE_COUNT, /* defaultValue= */ 0))
-                        .isEqualTo(Config.LOG_LIST_UPDATE_FAILURE_THRESHOLD);
-        verify(mLogger, times(1)).logCTLogListUpdateFailedEvent(
-                CERTIFICATE_TRANSPARENCY_LOG_LIST_UPDATE_FAILED__FAILURE_REASON__FAILURE_NO_DISK_SPACE,
-                Config.LOG_LIST_UPDATE_FAILURE_THRESHOLD
-        );
+        assertThat(
+                        mDataStore.getPropertyInt(
+                                Config.LOG_LIST_UPDATE_FAILURE_COUNT, /* defaultValue= */ 0))
+                .isEqualTo(Config.LOG_LIST_UPDATE_FAILURE_THRESHOLD);
+        verify(mLogger, times(1))
+                .logCTLogListUpdateFailedEvent(
+                        CERTIFICATE_TRANSPARENCY_LOG_LIST_UPDATE_FAILED__FAILURE_REASON__FAILURE_NO_DISK_SPACE,
+                        Config.LOG_LIST_UPDATE_FAILURE_THRESHOLD);
     }
 
     @Test
     public void testDownloader_contentDownloadFail_failureThresholdNotMet_doesNotLog()
-                throws Exception {
-        long contentId = mCertificateTransparencyDownloader.startContentDownload();
+            throws Exception {
+        mCertificateTransparencyDownloader.startContentDownload(mCompatVersion);
         // Set the failure count to well below the threshold
         mDataStore.setPropertyInt(Config.LOG_LIST_UPDATE_FAILURE_COUNT, 0);
-        setFailedDownload(
-                contentId,
-                // Failure cases where we give up on the download.
-                DownloadManager.ERROR_INSUFFICIENT_SPACE,
-                DownloadManager.ERROR_HTTP_DATA_ERROR);
-        Intent downloadCompleteIntent = makeDownloadCompleteIntent(contentId);
 
-        mCertificateTransparencyDownloader.onReceive(mContext, downloadCompleteIntent);
+        mCertificateTransparencyDownloader.onReceive(
+                mContext,
+                makeContentDownloadFailedIntent(
+                        mCompatVersion, DownloadManager.ERROR_HTTP_DATA_ERROR));
 
-        assertThat(mDataStore.getPropertyInt(
-                Config.LOG_LIST_UPDATE_FAILURE_COUNT, /* defaultValue= */ 0))
-                        .isEqualTo(1);
+        assertThat(
+                        mDataStore.getPropertyInt(
+                                Config.LOG_LIST_UPDATE_FAILURE_COUNT, /* defaultValue= */ 0))
+                .isEqualTo(1);
         verify(mLogger, never()).logCTLogListUpdateFailedEvent(anyInt(), anyInt());
     }
 
     @Test
-    public void testDownloader_contentDownloadSuccess_installFail_doNotUpdateDataStore()
+    public void testDownloader_contentDownloadSuccess_invalidLogList_installFails()
             throws Exception {
-        File logListFile = makeLogListFile("456");
-        File metadataFile = sign(logListFile);
+        File invalidLogListFile = writeToFile("not_a_json_log_list".getBytes());
+        File metadataFile = sign(invalidLogListFile);
         mSignatureVerifier.setPublicKey(mPublicKey);
-        long metadataId = mCertificateTransparencyDownloader.startMetadataDownload();
-        setSuccessfulDownload(metadataId, metadataFile);
-        long contentId = mCertificateTransparencyDownloader.startContentDownload();
-        setSuccessfulDownload(contentId, logListFile);
-        when(mCertificateTransparencyInstaller.install(
-                        eq(Config.COMPATIBILITY_VERSION), any(), anyString()))
-                .thenReturn(false);
+        mCertificateTransparencyDownloader.startMetadataDownload();
 
         assertNoVersionIsInstalled();
         mCertificateTransparencyDownloader.onReceive(
-                mContext, makeDownloadCompleteIntent(contentId));
+                mContext, makeMetadataDownloadCompleteIntent(mCompatVersion, metadataFile));
+        mCertificateTransparencyDownloader.onReceive(
+                mContext, makeContentDownloadCompleteIntent(mCompatVersion, invalidLogListFile));
 
         assertNoVersionIsInstalled();
     }
@@ -426,30 +407,31 @@
         File logListFile = makeLogListFile("456");
         File metadataFile = sign(logListFile);
         mSignatureVerifier.setPublicKey(mPublicKey);
-        long metadataId = mCertificateTransparencyDownloader.startMetadataDownload();
-        setSuccessfulDownload(metadataId, metadataFile);
-        long contentId = mCertificateTransparencyDownloader.startContentDownload();
-        setSuccessfulDownload(contentId, logListFile);
+        mCertificateTransparencyDownloader.startMetadataDownload();
         // Set the failure count to just below the threshold
-        mDataStore.setPropertyInt(Config.LOG_LIST_UPDATE_FAILURE_COUNT,
-                Config.LOG_LIST_UPDATE_FAILURE_THRESHOLD - 1);
+        mDataStore.setPropertyInt(
+                Config.LOG_LIST_UPDATE_FAILURE_COUNT, Config.LOG_LIST_UPDATE_FAILURE_THRESHOLD - 1);
 
         // Set the public key to be missing
         mSignatureVerifier.resetPublicKey();
         mCertificateTransparencyDownloader.onReceive(
-                mContext, makeDownloadCompleteIntent(contentId));
+                mContext, makeMetadataDownloadCompleteIntent(mCompatVersion, metadataFile));
+        mCertificateTransparencyDownloader.onReceive(
+                mContext, makeContentDownloadCompleteIntent(mCompatVersion, logListFile));
 
-        assertThat(mDataStore.getPropertyInt(
-                Config.LOG_LIST_UPDATE_FAILURE_COUNT, /* defaultValue= */ 0))
-                        .isEqualTo(Config.LOG_LIST_UPDATE_FAILURE_THRESHOLD);
-        verify(mLogger, times(1)).logCTLogListUpdateFailedEvent(
-                CERTIFICATE_TRANSPARENCY_LOG_LIST_UPDATE_FAILED__FAILURE_REASON__FAILURE_SIGNATURE_NOT_FOUND,
-                Config.LOG_LIST_UPDATE_FAILURE_THRESHOLD
-        );
-        verify(mLogger, never()).logCTLogListUpdateFailedEvent(
-                eq(CERTIFICATE_TRANSPARENCY_LOG_LIST_UPDATE_FAILED__FAILURE_REASON__FAILURE_SIGNATURE_VERIFICATION),
-                anyInt()
-        );
+        assertThat(
+                        mDataStore.getPropertyInt(
+                                Config.LOG_LIST_UPDATE_FAILURE_COUNT, /* defaultValue= */ 0))
+                .isEqualTo(Config.LOG_LIST_UPDATE_FAILURE_THRESHOLD);
+        verify(mLogger, times(1))
+                .logCTLogListUpdateFailedEvent(
+                        CERTIFICATE_TRANSPARENCY_LOG_LIST_UPDATE_FAILED__FAILURE_REASON__FAILURE_SIGNATURE_NOT_FOUND,
+                        Config.LOG_LIST_UPDATE_FAILURE_THRESHOLD);
+        verify(mLogger, never())
+                .logCTLogListUpdateFailedEvent(
+                        eq(
+                                CERTIFICATE_TRANSPARENCY_LOG_LIST_UPDATE_FAILED__FAILURE_REASON__FAILURE_SIGNATURE_VERIFICATION),
+                        anyInt());
     }
 
     @Test
@@ -464,31 +446,31 @@
         KeyPairGenerator instance = KeyPairGenerator.getInstance("EC");
         mSignatureVerifier.setPublicKey(instance.generateKeyPair().getPublic());
 
-        long metadataId = mCertificateTransparencyDownloader.startMetadataDownload();
-        setSuccessfulDownload(metadataId, metadataFile);
-        long contentId = mCertificateTransparencyDownloader.startContentDownload();
-        setSuccessfulDownload(contentId, logListFile);
-
         // Set the failure count to just below the threshold
-        mDataStore.setPropertyInt(Config.LOG_LIST_UPDATE_FAILURE_COUNT,
-                Config.LOG_LIST_UPDATE_FAILURE_THRESHOLD - 1);
+        mDataStore.setPropertyInt(
+                Config.LOG_LIST_UPDATE_FAILURE_COUNT, Config.LOG_LIST_UPDATE_FAILURE_THRESHOLD - 1);
 
         // Act
+        mCertificateTransparencyDownloader.startMetadataDownload();
         mCertificateTransparencyDownloader.onReceive(
-                mContext, makeDownloadCompleteIntent(contentId));
+                mContext, makeMetadataDownloadCompleteIntent(mCompatVersion, metadataFile));
+        mCertificateTransparencyDownloader.onReceive(
+                mContext, makeContentDownloadCompleteIntent(mCompatVersion, logListFile));
 
         // Assert
-        assertThat(mDataStore.getPropertyInt(
-                Config.LOG_LIST_UPDATE_FAILURE_COUNT, /* defaultValue= */ 0))
-                        .isEqualTo(Config.LOG_LIST_UPDATE_FAILURE_THRESHOLD);
-        verify(mLogger, never()).logCTLogListUpdateFailedEvent(
-                eq(CERTIFICATE_TRANSPARENCY_LOG_LIST_UPDATE_FAILED__FAILURE_REASON__FAILURE_SIGNATURE_NOT_FOUND),
-                anyInt()
-        );
-        verify(mLogger, times(1)).logCTLogListUpdateFailedEvent(
-                CERTIFICATE_TRANSPARENCY_LOG_LIST_UPDATE_FAILED__FAILURE_REASON__FAILURE_SIGNATURE_VERIFICATION,
-                Config.LOG_LIST_UPDATE_FAILURE_THRESHOLD
-        );
+        assertThat(
+                        mDataStore.getPropertyInt(
+                                Config.LOG_LIST_UPDATE_FAILURE_COUNT, /* defaultValue= */ 0))
+                .isEqualTo(Config.LOG_LIST_UPDATE_FAILURE_THRESHOLD);
+        verify(mLogger, never())
+                .logCTLogListUpdateFailedEvent(
+                        eq(
+                                CERTIFICATE_TRANSPARENCY_LOG_LIST_UPDATE_FAILED__FAILURE_REASON__FAILURE_SIGNATURE_NOT_FOUND),
+                        anyInt());
+        verify(mLogger, times(1))
+                .logCTLogListUpdateFailedEvent(
+                        CERTIFICATE_TRANSPARENCY_LOG_LIST_UPDATE_FAILED__FAILURE_REASON__FAILURE_SIGNATURE_VERIFICATION,
+                        Config.LOG_LIST_UPDATE_FAILURE_THRESHOLD);
     }
 
     @Test
@@ -503,31 +485,31 @@
         KeyPairGenerator instance = KeyPairGenerator.getInstance("RSA");
         mSignatureVerifier.setPublicKey(instance.generateKeyPair().getPublic());
 
-        long metadataId = mCertificateTransparencyDownloader.startMetadataDownload();
-        setSuccessfulDownload(metadataId, metadataFile);
-        long contentId = mCertificateTransparencyDownloader.startContentDownload();
-        setSuccessfulDownload(contentId, logListFile);
-
         // Set the failure count to just below the threshold
-        mDataStore.setPropertyInt(Config.LOG_LIST_UPDATE_FAILURE_COUNT,
-                Config.LOG_LIST_UPDATE_FAILURE_THRESHOLD - 1);
+        mDataStore.setPropertyInt(
+                Config.LOG_LIST_UPDATE_FAILURE_COUNT, Config.LOG_LIST_UPDATE_FAILURE_THRESHOLD - 1);
 
         // Act
+        mCertificateTransparencyDownloader.startMetadataDownload();
         mCertificateTransparencyDownloader.onReceive(
-                mContext, makeDownloadCompleteIntent(contentId));
+                mContext, makeMetadataDownloadCompleteIntent(mCompatVersion, metadataFile));
+        mCertificateTransparencyDownloader.onReceive(
+                mContext, makeContentDownloadCompleteIntent(mCompatVersion, logListFile));
 
         // Assert
-        assertThat(mDataStore.getPropertyInt(
-                Config.LOG_LIST_UPDATE_FAILURE_COUNT, /* defaultValue= */ 0))
-                        .isEqualTo(Config.LOG_LIST_UPDATE_FAILURE_THRESHOLD);
-        verify(mLogger, never()).logCTLogListUpdateFailedEvent(
-                eq(CERTIFICATE_TRANSPARENCY_LOG_LIST_UPDATE_FAILED__FAILURE_REASON__FAILURE_SIGNATURE_NOT_FOUND),
-                anyInt()
-        );
-        verify(mLogger, times(1)).logCTLogListUpdateFailedEvent(
-                CERTIFICATE_TRANSPARENCY_LOG_LIST_UPDATE_FAILED__FAILURE_REASON__FAILURE_SIGNATURE_VERIFICATION,
-                Config.LOG_LIST_UPDATE_FAILURE_THRESHOLD
-        );
+        assertThat(
+                        mDataStore.getPropertyInt(
+                                Config.LOG_LIST_UPDATE_FAILURE_COUNT, /* defaultValue= */ 0))
+                .isEqualTo(Config.LOG_LIST_UPDATE_FAILURE_THRESHOLD);
+        verify(mLogger, never())
+                .logCTLogListUpdateFailedEvent(
+                        eq(
+                                CERTIFICATE_TRANSPARENCY_LOG_LIST_UPDATE_FAILED__FAILURE_REASON__FAILURE_SIGNATURE_NOT_FOUND),
+                        anyInt());
+        verify(mLogger, times(1))
+                .logCTLogListUpdateFailedEvent(
+                        CERTIFICATE_TRANSPARENCY_LOG_LIST_UPDATE_FAILED__FAILURE_REASON__FAILURE_SIGNATURE_VERIFICATION,
+                        Config.LOG_LIST_UPDATE_FAILURE_THRESHOLD);
     }
 
     @Test
@@ -536,84 +518,81 @@
                     throws Exception {
         File logListFile = makeLogListFile("456");
         File metadataFile = sign(logListFile);
-        // Set the public key wrong, so signature verification fails
-        mSignatureVerifier.setPublicKey(mPublicKey);
-        long metadataId = mCertificateTransparencyDownloader.startMetadataDownload();
-        setSuccessfulDownload(metadataId, metadataFile);
-        long contentId = mCertificateTransparencyDownloader.startContentDownload();
-        setSuccessfulDownload(contentId, logListFile);
+        // Set the key to be deliberately wrong by using diff key pair
+        KeyPairGenerator instance = KeyPairGenerator.getInstance("RSA");
+        mSignatureVerifier.setPublicKey(instance.generateKeyPair().getPublic());
         // Set the failure count to well below the threshold
         mDataStore.setPropertyInt(Config.LOG_LIST_UPDATE_FAILURE_COUNT, 0);
 
+        mCertificateTransparencyDownloader.startMetadataDownload();
         mCertificateTransparencyDownloader.onReceive(
-                mContext, makeDownloadCompleteIntent(contentId));
+                mContext, makeMetadataDownloadCompleteIntent(mCompatVersion, metadataFile));
+        mCertificateTransparencyDownloader.onReceive(
+                mContext, makeContentDownloadCompleteIntent(mCompatVersion, logListFile));
 
-        assertThat(mDataStore.getPropertyInt(
-                Config.LOG_LIST_UPDATE_FAILURE_COUNT, /* defaultValue= */ 0))
-                        .isEqualTo(1);
-        verify(mLogger, never()).logCTLogListUpdateFailedEvent(
-                eq(CERTIFICATE_TRANSPARENCY_LOG_LIST_UPDATE_FAILED__FAILURE_REASON__FAILURE_SIGNATURE_NOT_FOUND),
-                anyInt()
-        );
-        verify(mLogger, never()).logCTLogListUpdateFailedEvent(
-                eq(CERTIFICATE_TRANSPARENCY_LOG_LIST_UPDATE_FAILED__FAILURE_REASON__FAILURE_SIGNATURE_VERIFICATION),
-                anyInt()
-        );
+        assertThat(
+                        mDataStore.getPropertyInt(
+                                Config.LOG_LIST_UPDATE_FAILURE_COUNT, /* defaultValue= */ 0))
+                .isEqualTo(1);
+        verify(mLogger, never())
+                .logCTLogListUpdateFailedEvent(
+                        eq(
+                                CERTIFICATE_TRANSPARENCY_LOG_LIST_UPDATE_FAILED__FAILURE_REASON__FAILURE_SIGNATURE_NOT_FOUND),
+                        anyInt());
+        verify(mLogger, never())
+                .logCTLogListUpdateFailedEvent(
+                        eq(
+                                CERTIFICATE_TRANSPARENCY_LOG_LIST_UPDATE_FAILED__FAILURE_REASON__FAILURE_SIGNATURE_VERIFICATION),
+                        anyInt());
     }
 
     @Test
     public void
             testDownloader_contentDownloadSuccess_installFail_failureThresholdExceeded_logsFailure()
                     throws Exception {
-        File logListFile = makeLogListFile("456");
-        File metadataFile = sign(logListFile);
+        File invalidLogListFile = writeToFile("not_a_json_log_list".getBytes());
+        File metadataFile = sign(invalidLogListFile);
         mSignatureVerifier.setPublicKey(mPublicKey);
-        long metadataId = mCertificateTransparencyDownloader.startMetadataDownload();
-        setSuccessfulDownload(metadataId, metadataFile);
-        long contentId = mCertificateTransparencyDownloader.startContentDownload();
-        setSuccessfulDownload(contentId, logListFile);
         // Set the failure count to just below the threshold
-        mDataStore.setPropertyInt(Config.LOG_LIST_UPDATE_FAILURE_COUNT,
-                Config.LOG_LIST_UPDATE_FAILURE_THRESHOLD - 1);
-        when(mCertificateTransparencyInstaller.install(
-                        eq(Config.COMPATIBILITY_VERSION), any(), anyString()))
-                .thenReturn(false);
+        mDataStore.setPropertyInt(
+                Config.LOG_LIST_UPDATE_FAILURE_COUNT, Config.LOG_LIST_UPDATE_FAILURE_THRESHOLD - 1);
 
+        mCertificateTransparencyDownloader.startMetadataDownload();
         mCertificateTransparencyDownloader.onReceive(
-                mContext, makeDownloadCompleteIntent(contentId));
+                mContext, makeMetadataDownloadCompleteIntent(mCompatVersion, metadataFile));
+        mCertificateTransparencyDownloader.onReceive(
+                mContext, makeContentDownloadCompleteIntent(mCompatVersion, invalidLogListFile));
 
-        assertThat(mDataStore.getPropertyInt(
-                Config.LOG_LIST_UPDATE_FAILURE_COUNT, /* defaultValue= */ 0))
-                        .isEqualTo(Config.LOG_LIST_UPDATE_FAILURE_THRESHOLD);
-        verify(mLogger, times(1)).logCTLogListUpdateFailedEvent(
-                CERTIFICATE_TRANSPARENCY_LOG_LIST_UPDATE_FAILED__FAILURE_REASON__FAILURE_VERSION_ALREADY_EXISTS,
-                Config.LOG_LIST_UPDATE_FAILURE_THRESHOLD
-        );
+        assertThat(
+                        mDataStore.getPropertyInt(
+                                Config.LOG_LIST_UPDATE_FAILURE_COUNT, /* defaultValue= */ 0))
+                .isEqualTo(Config.LOG_LIST_UPDATE_FAILURE_THRESHOLD);
+        verify(mLogger, times(1))
+                .logCTLogListUpdateFailedEvent(
+                        CERTIFICATE_TRANSPARENCY_LOG_LIST_UPDATE_FAILED__FAILURE_REASON__FAILURE_VERSION_ALREADY_EXISTS,
+                        Config.LOG_LIST_UPDATE_FAILURE_THRESHOLD);
     }
 
     @Test
     public void
             testDownloader_contentDownloadSuccess_installFail_failureThresholdNotMet_doesNotLog()
                     throws Exception {
-        File logListFile = makeLogListFile("456");
-        File metadataFile = sign(logListFile);
+        File invalidLogListFile = writeToFile("not_a_json_log_list".getBytes());
+        File metadataFile = sign(invalidLogListFile);
         mSignatureVerifier.setPublicKey(mPublicKey);
-        long metadataId = mCertificateTransparencyDownloader.startMetadataDownload();
-        setSuccessfulDownload(metadataId, metadataFile);
-        long contentId = mCertificateTransparencyDownloader.startContentDownload();
-        setSuccessfulDownload(contentId, logListFile);
         // Set the failure count to well below the threshold
         mDataStore.setPropertyInt(Config.LOG_LIST_UPDATE_FAILURE_COUNT, 0);
-        when(mCertificateTransparencyInstaller.install(
-                        eq(Config.COMPATIBILITY_VERSION), any(), anyString()))
-                .thenReturn(false);
 
+        mCertificateTransparencyDownloader.startMetadataDownload();
         mCertificateTransparencyDownloader.onReceive(
-                mContext, makeDownloadCompleteIntent(contentId));
+                mContext, makeMetadataDownloadCompleteIntent(mCompatVersion, metadataFile));
+        mCertificateTransparencyDownloader.onReceive(
+                mContext, makeContentDownloadCompleteIntent(mCompatVersion, invalidLogListFile));
 
-        assertThat(mDataStore.getPropertyInt(
-                Config.LOG_LIST_UPDATE_FAILURE_COUNT, /* defaultValue= */ 0))
-                        .isEqualTo(1);
+        assertThat(
+                        mDataStore.getPropertyInt(
+                                Config.LOG_LIST_UPDATE_FAILURE_COUNT, /* defaultValue= */ 0))
+                .isEqualTo(1);
         verify(mLogger, never()).logCTLogListUpdateFailedEvent(anyInt(), anyInt());
     }
 
@@ -623,17 +602,14 @@
         File logListFile = makeLogListFile("456");
         File metadataFile = File.createTempFile("log_list-wrong_metadata", "sig");
         mSignatureVerifier.setPublicKey(mPublicKey);
-        long metadataId = mCertificateTransparencyDownloader.startMetadataDownload();
-        setSuccessfulDownload(metadataId, metadataFile);
-        long contentId = mCertificateTransparencyDownloader.startContentDownload();
-        setSuccessfulDownload(contentId, logListFile);
 
         assertNoVersionIsInstalled();
+        mCertificateTransparencyDownloader.startMetadataDownload();
         mCertificateTransparencyDownloader.onReceive(
-                mContext, makeDownloadCompleteIntent(contentId));
+                mContext, makeMetadataDownloadCompleteIntent(mCompatVersion, metadataFile));
+        mCertificateTransparencyDownloader.onReceive(
+                mContext, makeContentDownloadCompleteIntent(mCompatVersion, logListFile));
 
-        verify(mCertificateTransparencyInstaller, never())
-                .install(eq(Config.COMPATIBILITY_VERSION), any(), anyString());
         assertNoVersionIsInstalled();
     }
 
@@ -643,17 +619,14 @@
         File logListFile = makeLogListFile("456");
         File metadataFile = sign(logListFile);
         mSignatureVerifier.resetPublicKey();
-        long metadataId = mCertificateTransparencyDownloader.startMetadataDownload();
-        setSuccessfulDownload(metadataId, metadataFile);
-        long contentId = mCertificateTransparencyDownloader.startContentDownload();
-        setSuccessfulDownload(contentId, logListFile);
 
         assertNoVersionIsInstalled();
+        mCertificateTransparencyDownloader.startMetadataDownload();
         mCertificateTransparencyDownloader.onReceive(
-                mContext, makeDownloadCompleteIntent(contentId));
+                mContext, makeMetadataDownloadCompleteIntent(mCompatVersion, metadataFile));
+        mCertificateTransparencyDownloader.onReceive(
+                mContext, makeContentDownloadCompleteIntent(mCompatVersion, logListFile));
 
-        verify(mCertificateTransparencyInstaller, never())
-                .install(eq(Config.COMPATIBILITY_VERSION), any(), anyString());
         assertNoVersionIsInstalled();
     }
 
@@ -667,52 +640,37 @@
         assertNoVersionIsInstalled();
 
         // 1. Start download of public key.
-        long publicKeyId = mCertificateTransparencyDownloader.startPublicKeyDownload();
+        mCertificateTransparencyDownloader.startPublicKeyDownload();
 
-        // 2. On successful public key download, set the key and start the metatadata download.
-        setSuccessfulDownload(publicKeyId, publicKeyFile);
-
+        // 2. On successful public key download, set the key and start the metatadata
+        // download.
         mCertificateTransparencyDownloader.onReceive(
-                mContext, makeDownloadCompleteIntent(publicKeyId));
+                mContext, makePublicKeyDownloadCompleteIntent(publicKeyFile));
 
         // 3. On successful metadata download, start the content download.
-        long metadataId = mCertificateTransparencyDownloader.getMetadataDownloadId();
-        setSuccessfulDownload(metadataId, metadataFile);
-
         mCertificateTransparencyDownloader.onReceive(
-                mContext, makeDownloadCompleteIntent(metadataId));
+                mContext, makeMetadataDownloadCompleteIntent(mCompatVersion, metadataFile));
 
-        // 4. On successful content download, verify the signature and install the new version.
-        long contentId = mCertificateTransparencyDownloader.getContentDownloadId();
-        setSuccessfulDownload(contentId, logListFile);
-        when(mCertificateTransparencyInstaller.install(
-                        eq(Config.COMPATIBILITY_VERSION), any(), anyString()))
-                .thenReturn(true);
-
+        // 4. On successful content download, verify the signature and install the new
+        // version.
         mCertificateTransparencyDownloader.onReceive(
-                mContext, makeDownloadCompleteIntent(contentId));
+                mContext, makeContentDownloadCompleteIntent(mCompatVersion, logListFile));
 
         assertInstallSuccessful(newVersion);
     }
 
     private void assertNoVersionIsInstalled() {
-        assertThat(mDataStore.getProperty(Config.VERSION)).isNull();
+        assertThat(mCompatVersion.getVersionDir().exists()).isFalse();
     }
 
     private void assertInstallSuccessful(String version) {
-        assertThat(mDataStore.getProperty(Config.VERSION)).isEqualTo(version);
-    }
-
-    private Intent makeDownloadCompleteIntent(long downloadId) {
-        return new Intent(DownloadManager.ACTION_DOWNLOAD_COMPLETE)
-                .putExtra(DownloadManager.EXTRA_DOWNLOAD_ID, downloadId);
-    }
-
-    private void prepareDataStore() {
-        mDataStore.load();
-        mDataStore.setProperty(Config.CONTENT_URL, Config.URL_LOG_LIST);
-        mDataStore.setProperty(Config.METADATA_URL, Config.URL_SIGNATURE);
-        mDataStore.setProperty(Config.PUBLIC_KEY_URL, Config.URL_PUBLIC_KEY);
+        File logsDir =
+                new File(
+                        mCompatVersion.getVersionDir(),
+                        CompatibilityVersion.LOGS_DIR_PREFIX + version);
+        assertThat(logsDir.exists()).isTrue();
+        File logsFile = new File(logsDir, CompatibilityVersion.LOGS_LIST_FILE_NAME);
+        assertThat(logsFile.exists()).isTrue();
     }
 
     private void prepareDownloadManager() {
@@ -720,6 +678,32 @@
                 .thenAnswer(invocation -> mNextDownloadId++);
     }
 
+    private Intent makePublicKeyDownloadCompleteIntent(File publicKeyfile) {
+        return makeDownloadCompleteIntent(
+                mCertificateTransparencyDownloader.getPublicKeyDownloadId(), publicKeyfile);
+    }
+
+    private Intent makeMetadataDownloadCompleteIntent(
+            CompatibilityVersion compatVersion, File signatureFile) {
+        return makeDownloadCompleteIntent(
+                mCertificateTransparencyDownloader.getMetadataDownloadId(compatVersion),
+                signatureFile);
+    }
+
+    private Intent makeContentDownloadCompleteIntent(
+            CompatibilityVersion compatVersion, File logListFile) {
+        return makeDownloadCompleteIntent(
+                mCertificateTransparencyDownloader.getContentDownloadId(compatVersion),
+                logListFile);
+    }
+
+    private Intent makeDownloadCompleteIntent(long downloadId, File file) {
+        when(mDownloadManager.query(any(Query.class))).thenReturn(makeSuccessfulDownloadCursor());
+        when(mDownloadManager.getUriForDownloadedFile(downloadId)).thenReturn(Uri.fromFile(file));
+        return new Intent(DownloadManager.ACTION_DOWNLOAD_COMPLETE)
+                .putExtra(DownloadManager.EXTRA_DOWNLOAD_ID, downloadId);
+    }
+
     private Cursor makeSuccessfulDownloadCursor() {
         MatrixCursor cursor =
                 new MatrixCursor(
@@ -730,9 +714,26 @@
         return cursor;
     }
 
-    private void setSuccessfulDownload(long downloadId, File file) {
-        when(mDownloadManager.query(any(Query.class))).thenReturn(makeSuccessfulDownloadCursor());
-        when(mDownloadManager.getUriForDownloadedFile(downloadId)).thenReturn(Uri.fromFile(file));
+    private Intent makePublicKeyDownloadFailedIntent(int error) {
+        return makeDownloadFailedIntent(
+                mCertificateTransparencyDownloader.getPublicKeyDownloadId(), error);
+    }
+
+    private Intent makeMetadataDownloadFailedIntent(CompatibilityVersion compatVersion, int error) {
+        return makeDownloadFailedIntent(
+                mCertificateTransparencyDownloader.getMetadataDownloadId(compatVersion), error);
+    }
+
+    private Intent makeContentDownloadFailedIntent(CompatibilityVersion compatVersion, int error) {
+        return makeDownloadFailedIntent(
+                mCertificateTransparencyDownloader.getContentDownloadId(compatVersion), error);
+    }
+
+    private Intent makeDownloadFailedIntent(long downloadId, int error) {
+        when(mDownloadManager.query(any(Query.class))).thenReturn(makeFailedDownloadCursor(error));
+        when(mDownloadManager.getUriForDownloadedFile(downloadId)).thenReturn(null);
+        return new Intent(DownloadManager.ACTION_DOWNLOAD_COMPLETE)
+                .putExtra(DownloadManager.EXTRA_DOWNLOAD_ID, downloadId);
     }
 
     private Cursor makeFailedDownloadCursor(int error) {
@@ -745,16 +746,6 @@
         return cursor;
     }
 
-    private void setFailedDownload(long downloadId, int... downloadManagerErrors) {
-        Cursor first = makeFailedDownloadCursor(downloadManagerErrors[0]);
-        Cursor[] others = new Cursor[downloadManagerErrors.length - 1];
-        for (int i = 1; i < downloadManagerErrors.length; i++) {
-            others[i - 1] = makeFailedDownloadCursor(downloadManagerErrors[i]);
-        }
-        when(mDownloadManager.query(any())).thenReturn(first, others);
-        when(mDownloadManager.getUriForDownloadedFile(downloadId)).thenReturn(null);
-    }
-
     private File writePublicKeyToFile(PublicKey publicKey)
             throws IOException, GeneralSecurityException {
         return writeToFile(Base64.getEncoder().encode(publicKey.getEncoded()));
diff --git a/networksecurity/tests/unit/src/com/android/server/net/ct/CertificateTransparencyInstallerTest.java b/networksecurity/tests/unit/src/com/android/server/net/ct/CertificateTransparencyInstallerTest.java
deleted file mode 100644
index 50d3f23..0000000
--- a/networksecurity/tests/unit/src/com/android/server/net/ct/CertificateTransparencyInstallerTest.java
+++ /dev/null
@@ -1,183 +0,0 @@
-/*
- * Copyright (C) 2024 The Android Open Source Project
- *
- * Licensed under the Apache License, Version 2.0 (the "License");
- * you may not use this file except in compliance with the License.
- * You may obtain a copy of the License at
- *
- *      http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing, software
- * distributed under the License is distributed on an "AS IS" BASIS,
- * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
- * See the License for the specific language governing permissions and
- * limitations under the License.
- */
-package com.android.server.net.ct;
-
-import static com.google.common.truth.Truth.assertThat;
-
-import androidx.test.platform.app.InstrumentationRegistry;
-
-import org.junit.After;
-import org.junit.Before;
-import org.junit.Test;
-import org.junit.runner.RunWith;
-import org.junit.runners.JUnit4;
-
-import java.io.ByteArrayInputStream;
-import java.io.File;
-import java.io.FileInputStream;
-import java.io.FileOutputStream;
-import java.io.IOException;
-import java.io.InputStream;
-import java.io.OutputStream;
-
-/** Tests for the {@link CertificateTransparencyInstaller}. */
-@RunWith(JUnit4.class)
-public class CertificateTransparencyInstallerTest {
-
-    private static final String TEST_VERSION = "test-v1";
-
-    private File mTestDir =
-            new File(
-                    InstrumentationRegistry.getInstrumentation().getContext().getFilesDir(),
-                    "test-dir");
-    private CertificateTransparencyInstaller mCertificateTransparencyInstaller =
-            new CertificateTransparencyInstaller(mTestDir);
-
-    @Before
-    public void setUp() {
-        mCertificateTransparencyInstaller.addCompatibilityVersion(TEST_VERSION);
-    }
-
-    @After
-    public void tearDown() {
-        mCertificateTransparencyInstaller.removeCompatibilityVersion(TEST_VERSION);
-        DirectoryUtils.removeDir(mTestDir);
-    }
-
-    @Test
-    public void testCompatibilityVersion_installSuccessful() throws IOException {
-        assertThat(mTestDir.mkdir()).isTrue();
-        String content = "i_am_compatible";
-        String version = "i_am_version";
-        CompatibilityVersion compatVersion =
-                mCertificateTransparencyInstaller.getCompatibilityVersion(TEST_VERSION);
-
-        try (InputStream inputStream = asStream(content)) {
-            assertThat(compatVersion.install(inputStream, version)).isTrue();
-        }
-        File logsDir = compatVersion.getLogsDir();
-        assertThat(logsDir.exists()).isTrue();
-        assertThat(logsDir.isDirectory()).isTrue();
-        assertThat(logsDir.getAbsolutePath())
-                .startsWith(mTestDir.getAbsolutePath() + "/" + TEST_VERSION);
-        File logsListFile = compatVersion.getLogsFile();
-        assertThat(logsListFile.exists()).isTrue();
-        assertThat(logsListFile.getAbsolutePath()).startsWith(logsDir.getAbsolutePath());
-        assertThat(readAsString(logsListFile)).isEqualTo(content);
-        File logsSymlink = compatVersion.getLogsDirSymlink();
-        assertThat(logsSymlink.exists()).isTrue();
-        assertThat(logsSymlink.isDirectory()).isTrue();
-        assertThat(logsSymlink.getAbsolutePath())
-                .startsWith(mTestDir.getAbsolutePath() + "/" + TEST_VERSION + "/current");
-        assertThat(logsSymlink.getCanonicalPath()).isEqualTo(logsDir.getCanonicalPath());
-
-        assertThat(compatVersion.delete()).isTrue();
-        assertThat(logsDir.exists()).isFalse();
-        assertThat(logsSymlink.exists()).isFalse();
-        assertThat(logsListFile.exists()).isFalse();
-    }
-
-    @Test
-    public void testCompatibilityVersion_versionInstalledFailed() throws IOException {
-        assertThat(mTestDir.mkdir()).isTrue();
-
-        CompatibilityVersion compatVersion =
-                mCertificateTransparencyInstaller.getCompatibilityVersion(TEST_VERSION);
-        File rootDir = compatVersion.getRootDir();
-        assertThat(rootDir.mkdir()).isTrue();
-
-        String existingVersion = "666";
-        File existingLogDir =
-                new File(rootDir, CompatibilityVersion.LOGS_DIR_PREFIX + existingVersion);
-        assertThat(existingLogDir.mkdir()).isTrue();
-
-        String existingContent = "somebody_tried_to_install_me_but_failed_halfway_through";
-        File logsListFile = new File(existingLogDir, CompatibilityVersion.LOGS_LIST_FILE_NAME);
-        assertThat(logsListFile.createNewFile()).isTrue();
-        writeToFile(logsListFile, existingContent);
-
-        String newContent = "i_am_the_real_content";
-        try (InputStream inputStream = asStream(newContent)) {
-            assertThat(compatVersion.install(inputStream, existingVersion)).isTrue();
-        }
-
-        assertThat(readAsString(logsListFile)).isEqualTo(newContent);
-    }
-
-    @Test
-    public void testCertificateTransparencyInstaller_installSuccessfully() throws IOException {
-        String content = "i_am_a_certificate_and_i_am_transparent";
-        String version = "666";
-
-        try (InputStream inputStream = asStream(content)) {
-            assertThat(
-                            mCertificateTransparencyInstaller.install(
-                                    TEST_VERSION, inputStream, version))
-                    .isTrue();
-        }
-
-        assertThat(mTestDir.exists()).isTrue();
-        assertThat(mTestDir.isDirectory()).isTrue();
-        CompatibilityVersion compatVersion =
-                mCertificateTransparencyInstaller.getCompatibilityVersion(TEST_VERSION);
-        File logsDir = compatVersion.getLogsDir();
-        assertThat(logsDir.exists()).isTrue();
-        assertThat(logsDir.isDirectory()).isTrue();
-        assertThat(logsDir.getAbsolutePath())
-                .startsWith(mTestDir.getAbsolutePath() + "/" + TEST_VERSION);
-        File logsListFile = compatVersion.getLogsFile();
-        assertThat(logsListFile.exists()).isTrue();
-        assertThat(logsListFile.getAbsolutePath()).startsWith(logsDir.getAbsolutePath());
-        assertThat(readAsString(logsListFile)).isEqualTo(content);
-    }
-
-    @Test
-    public void testCertificateTransparencyInstaller_versionIsAlreadyInstalled()
-            throws IOException {
-        String existingVersion = "666";
-        String existingContent = "i_was_already_installed_successfully";
-        CompatibilityVersion compatVersion =
-                mCertificateTransparencyInstaller.getCompatibilityVersion(TEST_VERSION);
-
-        DirectoryUtils.makeDir(mTestDir);
-        try (InputStream inputStream = asStream(existingContent)) {
-            assertThat(compatVersion.install(inputStream, existingVersion)).isTrue();
-        }
-
-        try (InputStream inputStream = asStream("i_will_be_ignored")) {
-            assertThat(
-                            mCertificateTransparencyInstaller.install(
-                                    TEST_VERSION, inputStream, existingVersion))
-                    .isFalse();
-        }
-
-        assertThat(readAsString(compatVersion.getLogsFile())).isEqualTo(existingContent);
-    }
-
-    private static InputStream asStream(String string) throws IOException {
-        return new ByteArrayInputStream(string.getBytes());
-    }
-
-    private static String readAsString(File file) throws IOException {
-        return new String(new FileInputStream(file).readAllBytes());
-    }
-
-    private static void writeToFile(File file, String string) throws IOException {
-        try (OutputStream out = new FileOutputStream(file)) {
-            out.write(string.getBytes());
-        }
-    }
-}
diff --git a/networksecurity/tests/unit/src/com/android/server/net/ct/CompatibilityVersionTest.java b/networksecurity/tests/unit/src/com/android/server/net/ct/CompatibilityVersionTest.java
new file mode 100644
index 0000000..38fff48
--- /dev/null
+++ b/networksecurity/tests/unit/src/com/android/server/net/ct/CompatibilityVersionTest.java
@@ -0,0 +1,180 @@
+/*
+ * Copyright (C) 2024 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package com.android.server.net.ct;
+
+import static com.google.common.truth.Truth.assertThat;
+
+import androidx.test.platform.app.InstrumentationRegistry;
+
+import org.json.JSONException;
+import org.json.JSONObject;
+import org.junit.After;
+import org.junit.Test;
+import org.junit.runner.RunWith;
+import org.junit.runners.JUnit4;
+
+import java.io.ByteArrayInputStream;
+import java.io.File;
+import java.io.FileInputStream;
+import java.io.IOException;
+import java.io.InputStream;
+
+/** Tests for the {@link CompatibilityVersion}. */
+@RunWith(JUnit4.class)
+public class CompatibilityVersionTest {
+
+    private static final String TEST_VERSION = "v123";
+
+    private final File mTestDir =
+            InstrumentationRegistry.getInstrumentation().getContext().getFilesDir();
+    private final CompatibilityVersion mCompatVersion =
+            new CompatibilityVersion(
+                    TEST_VERSION, Config.URL_SIGNATURE, Config.URL_LOG_LIST, mTestDir);
+
+    @After
+    public void tearDown() {
+        mCompatVersion.delete();
+    }
+
+    @Test
+    public void testCompatibilityVersion_versionDirectory_setupSuccessful() {
+        File versionDir = mCompatVersion.getVersionDir();
+        assertThat(versionDir.exists()).isFalse();
+        assertThat(versionDir.getAbsolutePath()).startsWith(mTestDir.getAbsolutePath());
+        assertThat(versionDir.getAbsolutePath()).endsWith(TEST_VERSION);
+    }
+
+    @Test
+    public void testCompatibilityVersion_symlink_setupSuccessful() {
+        File dirSymlink = mCompatVersion.getLogsDirSymlink();
+        assertThat(dirSymlink.exists()).isFalse();
+        assertThat(dirSymlink.getAbsolutePath())
+                .startsWith(mCompatVersion.getVersionDir().getAbsolutePath());
+    }
+
+    @Test
+    public void testCompatibilityVersion_logsFile_setupSuccessful() {
+        File logsFile = mCompatVersion.getLogsFile();
+        assertThat(logsFile.exists()).isFalse();
+        assertThat(logsFile.getAbsolutePath())
+                .startsWith(mCompatVersion.getLogsDirSymlink().getAbsolutePath());
+    }
+
+    @Test
+    public void testCompatibilityVersion_installSuccessful() throws Exception {
+        String version = "i_am_version";
+        JSONObject logList = makeLogList(version, "i_am_content");
+
+        try (InputStream inputStream = asStream(logList)) {
+            assertThat(mCompatVersion.install(inputStream)).isTrue();
+        }
+
+        File logListFile = mCompatVersion.getLogsFile();
+        assertThat(logListFile.exists()).isTrue();
+        assertThat(logListFile.getCanonicalPath())
+                .isEqualTo(
+                        // <path-to-test-files>/v123/logs-i_am_version/log_list.json
+                        new File(
+                                        new File(
+                                                mCompatVersion.getVersionDir(),
+                                                CompatibilityVersion.LOGS_DIR_PREFIX + version),
+                                        CompatibilityVersion.LOGS_LIST_FILE_NAME)
+                                .getCanonicalPath());
+        assertThat(logListFile.getAbsolutePath())
+                .isEqualTo(
+                        // <path-to-test-files>/v123/current/log_list.json
+                        new File(
+                                        new File(
+                                                mCompatVersion.getVersionDir(),
+                                                CompatibilityVersion.CURRENT_LOGS_DIR_SYMLINK_NAME),
+                                        CompatibilityVersion.LOGS_LIST_FILE_NAME)
+                                .getAbsolutePath());
+    }
+
+    @Test
+    public void testCompatibilityVersion_deleteSuccessfully() throws Exception {
+        try (InputStream inputStream = asStream(makeLogList(/* version= */ "123"))) {
+            assertThat(mCompatVersion.install(inputStream)).isTrue();
+        }
+
+        mCompatVersion.delete();
+
+        assertThat(mCompatVersion.getLogsFile().exists()).isFalse();
+    }
+
+    @Test
+    public void testCompatibilityVersion_invalidLogList() throws Exception {
+        try (InputStream inputStream = new ByteArrayInputStream(("not_a_valid_list".getBytes()))) {
+            assertThat(mCompatVersion.install(inputStream)).isFalse();
+        }
+
+        assertThat(mCompatVersion.getLogsFile().exists()).isFalse();
+    }
+
+    @Test
+    public void testCompatibilityVersion_incompleteVersionExists_replacesOldVersion()
+            throws Exception {
+        String existingVersion = "666";
+        File existingLogDir =
+                new File(
+                        mCompatVersion.getVersionDir(),
+                        CompatibilityVersion.LOGS_DIR_PREFIX + existingVersion);
+        assertThat(existingLogDir.mkdirs()).isTrue();
+        File logsListFile = new File(existingLogDir, CompatibilityVersion.LOGS_LIST_FILE_NAME);
+        assertThat(logsListFile.createNewFile()).isTrue();
+
+        JSONObject newLogList = makeLogList(existingVersion, "i_am_the_real_content");
+        try (InputStream inputStream = asStream(newLogList)) {
+            assertThat(mCompatVersion.install(inputStream)).isTrue();
+        }
+
+        assertThat(readAsString(logsListFile)).isEqualTo(newLogList.toString());
+    }
+
+    @Test
+    public void testCompatibilityVersion_versionAlreadyExists_installFails() throws Exception {
+        String existingVersion = "666";
+        JSONObject existingLogList = makeLogList(existingVersion, "i_was_installed_successfully");
+        try (InputStream inputStream = asStream(existingLogList)) {
+            assertThat(mCompatVersion.install(inputStream)).isTrue();
+        }
+
+        try (InputStream inputStream = asStream(makeLogList(existingVersion, "i_am_ignored"))) {
+            assertThat(mCompatVersion.install(inputStream)).isFalse();
+        }
+
+        assertThat(readAsString(mCompatVersion.getLogsFile()))
+                .isEqualTo(existingLogList.toString());
+    }
+
+    private static InputStream asStream(JSONObject logList) throws IOException {
+        return new ByteArrayInputStream(logList.toString().getBytes());
+    }
+
+    private static JSONObject makeLogList(String version) throws JSONException {
+        return new JSONObject().put("version", version);
+    }
+
+    private static JSONObject makeLogList(String version, String content) throws JSONException {
+        return makeLogList(version).put("content", content);
+    }
+
+    private static String readAsString(File file) throws IOException {
+        try (InputStream in = new FileInputStream(file)) {
+            return new String(in.readAllBytes());
+        }
+    }
+}