diff --git a/tools/droiddoc/src/Android.mk b/tools/droiddoc/src/Android.mk
index bf404b7..30270b5 100644
--- a/tools/droiddoc/src/Android.mk
+++ b/tools/droiddoc/src/Android.mk
@@ -47,6 +47,7 @@
 	SampleTagInfo.java \
     Scoped.java \
 	SeeTagInfo.java \
+	SinceTagger.java \
 	Sorter.java \
 	SourcePositionInfo.java \
     Stubs.java \
@@ -57,6 +58,7 @@
 	TypeInfo.java
 
 LOCAL_JAVA_LIBRARIES := \
+	apicheck \
 	clearsilver
 
 LOCAL_CLASSPATH := \
diff --git a/tools/droiddoc/src/ClassInfo.java b/tools/droiddoc/src/ClassInfo.java
index f397a83..869142e 100644
--- a/tools/droiddoc/src/ClassInfo.java
+++ b/tools/droiddoc/src/ClassInfo.java
@@ -907,6 +907,7 @@
         if (kind != null) {
             data.setValue("class.kind", kind);
         }
+        data.setValue("class.since", getSince());
 
         // the containing package -- note that this can be passed to type_link,
         // but it also contains the list of all of the packages
diff --git a/tools/droiddoc/src/DocInfo.java b/tools/droiddoc/src/DocInfo.java
index 2530dc2..3abb367 100644
--- a/tools/droiddoc/src/DocInfo.java
+++ b/tools/droiddoc/src/DocInfo.java
@@ -51,8 +51,17 @@
 
     public abstract ContainerInfo parent();
 
+    public void setSince(String since) {
+        mSince = since;
+    }
+
+    public String getSince() {
+        return mSince;
+    }
+
     private String mRawCommentText;
     Comment mComment;
     SourcePositionInfo mPosition;
+    private String mSince;
 }
 
diff --git a/tools/droiddoc/src/DroidDoc.java b/tools/droiddoc/src/DroidDoc.java
index 6f2b517..63fbc96 100644
--- a/tools/droiddoc/src/DroidDoc.java
+++ b/tools/droiddoc/src/DroidDoc.java
@@ -98,6 +98,7 @@
         String apiFile = null;
         String debugStubsFile = "";
         HashSet<String> stubPackages = null;
+        SinceTagger sinceTagger = new SinceTagger();
 
         root = r;
 
@@ -190,6 +191,9 @@
             else if (a[0].equals("-nodocs")) {
                 noDocs = true;
             }
+            else if (a[0].equals("-since")) {
+                sinceTagger.addVersion(a[1], a[2]);
+            }
         }
 
         // read some prefs from the template
@@ -203,6 +207,9 @@
         if (!noDocs) {
             long startTime = System.nanoTime();
 
+            // Apply @since tags from the XML file
+            sinceTagger.tagAll(Converter.rootClasses());
+
             // Files for proofreading
             if (proofreadFile != null) {
                 Proofread.initProofread(proofreadFile);
@@ -260,7 +267,7 @@
         if (stubsDir != null) {
             Stubs.writeStubs(stubsDir, apiXML, apiFile, stubPackages);
         }
-        
+
         Errors.printErrors();
         return !Errors.hadError;
     }
@@ -409,9 +416,12 @@
         if (option.equals("-nodocs")) {
             return 1;
         }
+        if (option.equals("-since")) {
+            return 3;
+        }
         return 0;
     }
-    
+
     public static boolean validOptions(String[][] options, DocErrorReporter r)
     {
         for (String[] a: options) {
@@ -777,6 +787,7 @@
         String name = pkg.name();
 
         data.setValue("package.name", name);
+        data.setValue("package.since", pkg.getSince());
         data.setValue("package.descr", "...description...");
 
         makeClassListHDF(data, "package.interfaces", 
diff --git a/tools/droiddoc/src/Errors.java b/tools/droiddoc/src/Errors.java
index dfeac88..95439f1 100644
--- a/tools/droiddoc/src/Errors.java
+++ b/tools/droiddoc/src/Errors.java
@@ -114,6 +114,7 @@
     public static Error DEPRECATION_MISMATCH = new Error(13, WARNING);
     public static Error MISSING_COMMENT = new Error(14, WARNING);
     public static Error IO_ERROR = new Error(15, HIDDEN);
+    public static Error NO_SINCE_DATA = new Error(16, WARNING);
 
     public static Error[] ERRORS = {
             UNRESOLVED_LINK,
@@ -129,6 +130,7 @@
             HIDDEN_SUPERCLASS,
             DEPRECATED,
             IO_ERROR,
+            NO_SINCE_DATA,
         };
 
     public static boolean setErrorLevel(int code, int level) {
diff --git a/tools/droiddoc/src/FieldInfo.java b/tools/droiddoc/src/FieldInfo.java
index 536d798..1c975e4 100644
--- a/tools/droiddoc/src/FieldInfo.java
+++ b/tools/droiddoc/src/FieldInfo.java
@@ -223,6 +223,7 @@
         TagInfo.makeHDF(data, base + ".descr", inlineTags());
         TagInfo.makeHDF(data, base + ".deprecated", comment().deprecatedTags());
         TagInfo.makeHDF(data, base + ".seeAlso", comment().seeTags());
+        data.setValue(base + ".since", getSince());
         data.setValue(base + ".final", isFinal() ? "final" : "");
         data.setValue(base + ".static", isStatic() ? "static" : "");
         if (isPublic()) {
diff --git a/tools/droiddoc/src/MethodInfo.java b/tools/droiddoc/src/MethodInfo.java
index ca30665..bded88b 100644
--- a/tools/droiddoc/src/MethodInfo.java
+++ b/tools/droiddoc/src/MethodInfo.java
@@ -15,9 +15,8 @@
  */
 
 import org.clearsilver.HDF;
-import org.clearsilver.CS;
+
 import java.util.*;
-import java.io.*;
 
 public class MethodInfo extends MemberInfo
 {
@@ -357,6 +356,19 @@
         return s;
     }
 
+    /**
+     * Returns a name consistent with the {@link
+     * com.android.apicheck.MethodInfo#getHashableName()}.
+     */
+    public String getHashableName() {
+        StringBuilder result = new StringBuilder();
+        result.append(name());
+        for (ParameterInfo pInfo : mParameters) {
+            result.append(":").append(pInfo.type().fullName());
+        }
+        return result.toString();
+    }
+
     private boolean inList(ClassInfo item, ThrowsTagInfo[] list)
     {
         int len = list.length;
@@ -545,6 +557,7 @@
         TagInfo.makeHDF(data, base + ".descr", inlineTags());
         TagInfo.makeHDF(data, base + ".deprecated", deprecatedTags());
         TagInfo.makeHDF(data, base + ".seeAlso", seeTags());
+        data.setValue(base + ".since", getSince());
         ParamTagInfo.makeHDF(data, base + ".paramTags", paramTags());
         AttrTagInfo.makeReferenceHDF(data, base + ".attrRefs", comment().attrTags());
         ThrowsTagInfo.makeHDF(data, base + ".throws", throwsTags());
diff --git a/tools/droiddoc/src/SinceTagger.java b/tools/droiddoc/src/SinceTagger.java
new file mode 100644
index 0000000..a34814c
--- /dev/null
+++ b/tools/droiddoc/src/SinceTagger.java
@@ -0,0 +1,182 @@
+// Copyright 2009 Google Inc. All Rights Reserved.
+
+import com.android.apicheck.*;
+
+import java.util.*;
+
+/**
+ * Applies version information to the DroidDoc class model from apicheck XML
+ * files. Sample usage:
+ * <pre>
+ *   ClassInfo[] classInfos = ...
+ *
+ *   SinceTagger sinceTagger = new SinceTagger()
+ *   sinceTagger.addVersion("frameworks/base/api/1.xml", "Android 1.0")
+ *   sinceTagger.addVersion("frameworks/base/api/2.xml", "Android 1.5")
+ *   sinceTagger.tagAll(...);
+ * </pre>
+ */
+public class SinceTagger {
+
+    private final Map<String, String> xmlToName
+            = new LinkedHashMap<String, String>();
+
+    /**
+     * Specifies the apicheck XML file and the API version it holds. Calls to
+     * this method should be called in order from oldest version to newest.
+     */
+    public void addVersion(String file, String name) {
+        xmlToName.put(file, name);
+    }
+
+    public void tagAll(ClassInfo[] classDocs) {
+        // read through the XML files in order, applying their since information
+        // to the Javadoc models
+        for (Map.Entry<String, String> versionSpec : xmlToName.entrySet()) {
+            String xmlFile = versionSpec.getKey();
+            String versionName = versionSpec.getValue();
+            ApiInfo specApi = new ApiCheck().parseApi(xmlFile);
+
+            applyVersionsFromSpec(versionName, specApi, classDocs);
+        }
+
+        if (!xmlToName.isEmpty()) {
+            warnForMissingVersions(classDocs);
+        }
+    }
+
+    /**
+     * Applies the version information to {@code classDocs} where not already
+     * present.
+     *
+     * @param versionName the version name
+     * @param specApi the spec for this version. If a symbol is in this spec, it
+     *      was present in the named version
+     * @param classDocs the doc model to update
+     */
+    private void applyVersionsFromSpec(String versionName,
+            ApiInfo specApi, ClassInfo[] classDocs) {
+        for (ClassInfo classDoc : classDocs) {
+            com.android.apicheck.PackageInfo packageSpec
+                    = specApi.getPackages().get(classDoc.containingPackage().name());
+
+            if (packageSpec == null) {
+                continue;
+            }
+
+            com.android.apicheck.ClassInfo classSpec
+                    = packageSpec.allClasses().get(classDoc.name());
+
+            if (classSpec == null) {
+                continue;
+            }
+
+            versionPackage(versionName, classDoc.containingPackage());
+            versionClass(versionName, classDoc);
+            versionConstructors(versionName, classSpec, classDoc);
+            versionFields(versionName, classSpec, classDoc);
+            versionMethods(versionName, classSpec, classDoc);
+        }
+    }
+
+    /**
+     * Applies version information to {@code doc} where not already present.
+     */
+    private void versionPackage(String versionName, PackageInfo doc) {
+        if (doc.getSince() == null) {
+            doc.setSince(versionName);
+        }
+    }
+
+    /**
+     * Applies version information to {@code doc} where not already present.
+     */
+    private void versionClass(String versionName, ClassInfo doc) {
+        if (doc.getSince() == null) {
+            doc.setSince(versionName);
+        }
+    }
+
+    /**
+     * Applies version information from {@code spec} to {@code doc} where not
+     * already present.
+     */
+    private void versionConstructors(String versionName,
+            com.android.apicheck.ClassInfo spec, ClassInfo doc) {
+        for (MethodInfo constructor : doc.constructors()) {
+            if (constructor.getSince() == null
+                    && spec.allConstructors().containsKey(constructor.getHashableName())) {
+                constructor.setSince(versionName);
+            }
+        }
+    }
+
+    /**
+     * Applies version information from {@code spec} to {@code doc} where not
+     * already present.
+     */
+    private void versionFields(String versionName,
+            com.android.apicheck.ClassInfo spec, ClassInfo doc) {
+        for (FieldInfo field : doc.fields()) {
+            if (field.getSince() == null
+                    && spec.allFields().containsKey(field.name())) {
+                field.setSince(versionName);
+            }
+        }
+    }
+
+    /**
+     * Applies version information from {@code spec} to {@code doc} where not
+     * already present.
+     */
+    private void versionMethods(String versionName,
+            com.android.apicheck.ClassInfo spec, ClassInfo doc) {
+        for (MethodInfo method : doc.methods()) {
+            if (method.getSince() != null) {
+                continue;
+            }
+
+            for (com.android.apicheck.ClassInfo superclass : spec.hierarchy()) {
+                if (superclass.allMethods().containsKey(method.getHashableName())) {
+                    method.setSince(versionName);
+                    break;
+                }
+            }
+        }
+    }
+
+    /**
+     * Warns if any symbols are missing version information. When configured
+     * properly, this will yield zero warnings because {@code apicheck}
+     * guarantees that all symbols are present in the most recent API.
+     */
+    private void warnForMissingVersions(ClassInfo[] classDocs) {
+        for (ClassInfo claz : classDocs) {
+            if (claz.getSince() == null) {
+                Errors.error(Errors.NO_SINCE_DATA, claz.position(),
+                        "XML missing class " + claz.qualifiedName());
+            }
+            for (FieldInfo field : claz.fields()) {
+                if (field.getSince() == null) {
+                    Errors.error(Errors.NO_SINCE_DATA, field.position(),
+                            "XML missing field "
+                                    + claz.qualifiedName() + "#" + field .name());
+                }
+            }
+            for (MethodInfo constructor : claz.constructors()) {
+                if (constructor.getSince() == null) {
+                    Errors.error(Errors.NO_SINCE_DATA, constructor.position(),
+                            "XML missing constructor "
+                                    + claz.qualifiedName() + "#" + constructor.getHashableName());
+                }
+            }
+            for (MethodInfo method : claz.methods()) {
+                if (method.getSince() == null) {
+                    Errors.error(Errors.NO_SINCE_DATA, method.position(),
+                            "XML missing method "
+                                    + claz.qualifiedName() + "#" + method .getHashableName());
+                }
+            }
+        }
+    }
+}