diff --git a/src/com/android/dialer/compat/CallAudioStateCompat.java b/src/com/android/dialer/compat/CallAudioStateCompat.java
new file mode 100644
index 0000000..51009d0
--- /dev/null
+++ b/src/com/android/dialer/compat/CallAudioStateCompat.java
@@ -0,0 +1,331 @@
+/*
+ * Copyright (C) 2015 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.dialer.compat;
+
+import android.os.Build;
+import android.os.Parcel;
+import android.os.Parcelable;
+import android.telecom.CallAudioState;
+
+import com.android.contacts.common.compat.SdkVersionOverride;
+
+import java.util.Locale;
+
+/**
+ * Compatibility class for {@link CallAudioState}
+ */
+public class CallAudioStateCompat {
+
+    /**
+     * Direct the audio stream through the device's earpiece.
+     */
+    public static final int ROUTE_EARPIECE = CallAudioState.ROUTE_EARPIECE;
+
+    /**
+     * Direct the audio stream through Bluetooth.
+     */
+    public static final int ROUTE_BLUETOOTH = CallAudioState.ROUTE_BLUETOOTH;
+
+    /**
+     * Direct the audio stream through a wired headset.
+     */
+    public static final int ROUTE_WIRED_HEADSET = CallAudioState.ROUTE_WIRED_HEADSET;
+
+    /**
+     * Direct the audio stream through the device's speakerphone.
+     */
+    public static final int ROUTE_SPEAKER = CallAudioState.ROUTE_SPEAKER;
+
+    /**
+     * Direct the audio stream through the device's earpiece or wired headset if one is connected.
+     */
+    public static final int ROUTE_WIRED_OR_EARPIECE = CallAudioState.ROUTE_WIRED_OR_EARPIECE;
+
+    private final CallAudioStateImpl mCallAudioState;
+
+    /**
+     * Constructor for a {@link CallAudioStateCompat} object.
+     *
+     * @param muted {@code true} if the call is muted, {@code false} otherwise.
+     * @param route The current audio route being used. Allowed values: {@link #ROUTE_EARPIECE}
+     * {@link #ROUTE_BLUETOOTH} {@link #ROUTE_WIRED_HEADSET} {@link #ROUTE_SPEAKER}
+     * @param supportedRouteMask Bit mask of all routes supported by this call. This should be a
+     * bitwise combination of the following values: {@link #ROUTE_EARPIECE} {@link #ROUTE_BLUETOOTH}
+     * {@link #ROUTE_WIRED_HEADSET} {@link #ROUTE_SPEAKER}
+     */
+    public CallAudioStateCompat(boolean muted, int route, int supportedRouteMask) {
+        if (SdkVersionOverride.getSdkVersion(Build.VERSION_CODES.M)
+                < Build.VERSION_CODES.M) {
+            mCallAudioState = new CallAudioStateBase(muted, route, supportedRouteMask);
+        } else {
+            mCallAudioState = new CallAudioStateMarshmallow(muted, route, supportedRouteMask);
+        }
+    }
+
+    /**
+     * @return {@code true} if the call is muted, {@code false} otherwise.
+     */
+    public boolean isMuted() {
+        return mCallAudioState.isMuted();
+    }
+
+    /**
+     * @return The current audio route being used.
+     */
+    public int getRoute() {
+        return mCallAudioState.getRoute();
+    }
+
+    /**
+     * @return Bit mask of all routes supported by this call.
+     */
+    public int getSupportedRouteMask() {
+        return mCallAudioState.getSupportedRouteMask();
+    }
+
+    /**
+     * Converts the provided audio route into a human readable string representation.
+     *
+     * @param route to convert into a string.
+     * @return String representation of the provided audio route.
+     */
+    public static String audioRouteToString(int route) {
+        if (SdkVersionOverride.getSdkVersion(Build.VERSION_CODES.M)
+                < Build.VERSION_CODES.M) {
+            return CallAudioStateBase.audioRouteToString(route);
+        }
+        return CallAudioStateMarshmallow.audioRouteToString(route);
+    }
+
+
+    @Override
+    public boolean equals(Object o) {
+        if (this == o) {
+            return true;
+        }
+        if (o == null || getClass() != o.getClass()) {
+            return false;
+        }
+
+        CallAudioStateCompat that = (CallAudioStateCompat) o;
+
+        return mCallAudioState.equals(that.mCallAudioState);
+
+    }
+
+    @Override
+    public int hashCode() {
+        return mCallAudioState.hashCode();
+    }
+
+    @Override
+    public String toString() {
+        return mCallAudioState.toString();
+    }
+
+    private interface CallAudioStateImpl {
+        boolean isMuted();
+        int getRoute();
+        int getSupportedRouteMask();
+    }
+
+    /**
+     * CallAudioStateImpl to use if the Sdk version is lower than
+     * {@link android.os.Build.VERSION_CODES.M}
+     *
+     * Coped from {@link android.telecom.CallAudioState}
+     *
+     * Encapsulates the telecom audio state, including the current audio routing, supported audio
+     * routing and mute.
+     */
+    private static class CallAudioStateBase implements CallAudioStateImpl, Parcelable {
+
+        /**
+         * Bit mask of all possible audio routes.
+         */
+        private static final int ROUTE_ALL = ROUTE_EARPIECE | ROUTE_BLUETOOTH | ROUTE_WIRED_HEADSET
+                | ROUTE_SPEAKER;
+
+        private final boolean isMuted;
+        private final int route;
+        private final int supportedRouteMask;
+
+        /**
+         * Constructor for a {@link CallAudioStateBase} object.
+         *
+         * @param muted {@code true} if the call is muted, {@code false} otherwise.
+         * @param route The current audio route being used. Allowed values: {@link #ROUTE_EARPIECE}
+         *      {@link #ROUTE_BLUETOOTH}, {@link #ROUTE_WIRED_HEADSET}, {@link #ROUTE_SPEAKER}
+         * @param supportedRouteMask Bit mask of all routes supported by this call. This should be a
+         *      bitwise combination of the following values: {@link #ROUTE_EARPIECE},
+         *      {@link #ROUTE_BLUETOOTH}, {@link #ROUTE_WIRED_HEADSET}, {@link #ROUTE_SPEAKER}
+         */
+        public CallAudioStateBase(boolean muted, int route, int supportedRouteMask) {
+            this.isMuted = muted;
+            this.route = route;
+            this.supportedRouteMask = supportedRouteMask;
+        }
+
+        @Override
+        public boolean equals(Object obj) {
+            if (obj == null) {
+                return false;
+            }
+            if (!(obj instanceof CallAudioStateBase)) {
+                return false;
+            }
+            CallAudioStateBase state = (CallAudioStateBase) obj;
+            return isMuted() == state.isMuted() && getRoute() == state.getRoute() &&
+                    getSupportedRouteMask() == state.getSupportedRouteMask();
+        }
+
+        @Override
+        public String toString() {
+            return String.format(Locale.US,
+                    "[AudioState isMuted: %b, route: %s, supportedRouteMask: %s]",
+                    isMuted,
+                    audioRouteToString(route),
+                    audioRouteToString(supportedRouteMask));
+        }
+
+        /**
+         * @return {@code true} if the call is muted, {@code false} otherwise.
+         */
+        @Override
+        public boolean isMuted() {
+            return isMuted;
+        }
+
+        /**
+         * @return The current audio route being used.
+         */
+        public int getRoute() {
+            return route;
+        }
+
+        /**
+         * @return Bit mask of all routes supported by this call.
+         */
+        public int getSupportedRouteMask() {
+            return supportedRouteMask;
+        }
+
+        /**
+         * Converts the provided audio route into a human readable string representation.
+         *
+         * @param route to convert into a string.
+         * @return String representation of the provided audio route.
+         */
+        public static String audioRouteToString(int route) {
+            if (route == 0 || (route & ~ROUTE_ALL) != 0x0) {
+                return "UNKNOWN";
+            }
+
+            StringBuffer buffer = new StringBuffer();
+            if ((route & ROUTE_EARPIECE) == ROUTE_EARPIECE) {
+                listAppend(buffer, "EARPIECE");
+            }
+            if ((route & ROUTE_BLUETOOTH) == ROUTE_BLUETOOTH) {
+                listAppend(buffer, "BLUETOOTH");
+            }
+            if ((route & ROUTE_WIRED_HEADSET) == ROUTE_WIRED_HEADSET) {
+                listAppend(buffer, "WIRED_HEADSET");
+            }
+            if ((route & ROUTE_SPEAKER) == ROUTE_SPEAKER) {
+                listAppend(buffer, "SPEAKER");
+            }
+
+            return buffer.toString();
+        }
+
+        /**
+         * Responsible for creating AudioState objects for deserialized Parcels.
+         */
+        public static final Parcelable.Creator<CallAudioStateBase> CREATOR =
+                new Parcelable.Creator<CallAudioStateBase>() {
+
+                    @Override
+                    public CallAudioStateBase createFromParcel(Parcel source) {
+                        boolean isMuted = source.readByte() == 0 ? false : true;
+                        int route = source.readInt();
+                        int supportedRouteMask = source.readInt();
+                        return new CallAudioStateBase(isMuted, route, supportedRouteMask);
+                    }
+
+                    @Override
+                    public CallAudioStateBase[] newArray(int size) {
+                        return new CallAudioStateBase[size];
+                    }
+                };
+
+        /**
+         * {@inheritDoc}
+         */
+        @Override
+        public int describeContents() {
+            return 0;
+        }
+
+        /**
+         * Writes AudioState object into a serializeable Parcel.
+         */
+        @Override
+        public void writeToParcel(Parcel destination, int flags) {
+            destination.writeByte((byte) (isMuted ? 1 : 0));
+            destination.writeInt(route);
+            destination.writeInt(supportedRouteMask);
+        }
+
+        private static void listAppend(StringBuffer buffer, String str) {
+            if (buffer.length() > 0) {
+                buffer.append(", ");
+            }
+            buffer.append(str);
+        }
+    }
+
+    /**
+     * CallAudioStateImpl to use if the Sdk version is at least
+     * {@link android.os.Build.VERSION_CODES.M}
+     */
+    private static class CallAudioStateMarshmallow implements CallAudioStateImpl {
+
+        private final CallAudioState mCallAudioStateDelegate;
+
+        public CallAudioStateMarshmallow(boolean muted, int route, int supportedRouteMask) {
+            mCallAudioStateDelegate = new CallAudioState(muted, route, supportedRouteMask);
+        }
+
+        @Override
+        public boolean isMuted() {
+            return mCallAudioStateDelegate.isMuted();
+        }
+
+        @Override
+        public int getRoute() {
+            return mCallAudioStateDelegate.getRoute();
+        }
+
+        @Override
+        public int getSupportedRouteMask() {
+            return mCallAudioStateDelegate.getSupportedRouteMask();
+        }
+
+        public static String audioRouteToString(int route) {
+            return CallAudioState.audioRouteToString(route);
+        }
+    }
+}
diff --git a/src/com/android/dialer/voicemail/VoicemailAudioManager.java b/src/com/android/dialer/voicemail/VoicemailAudioManager.java
index 267eeca..712b20b 100644
--- a/src/com/android/dialer/voicemail/VoicemailAudioManager.java
+++ b/src/com/android/dialer/voicemail/VoicemailAudioManager.java
@@ -19,10 +19,10 @@
 import android.content.Context;
 import android.media.AudioManager;
 import android.media.AudioManager.OnAudioFocusChangeListener;
-import android.telecom.CallAudioState;
 import android.util.Log;
 
-import java.util.Objects;
+import com.android.dialer.compat.CallAudioStateCompat;
+
 import java.util.concurrent.RejectedExecutionException;
 
 /**
@@ -38,7 +38,7 @@
     private VoicemailPlaybackPresenter mVoicemailPlaybackPresenter;
     private WiredHeadsetManager mWiredHeadsetManager;
     private boolean mWasSpeakerOn;
-    private CallAudioState mCallAudioState;
+    private CallAudioStateCompat mCallAudioState;
 
     public VoicemailAudioManager(Context context,
             VoicemailPlaybackPresenter voicemailPlaybackPresenter) {
@@ -82,25 +82,26 @@
 
         int newRoute = mCallAudioState.getRoute();  // start out with existing route
         if (newIsPluggedIn) {
-            newRoute = CallAudioState.ROUTE_WIRED_HEADSET;
+            newRoute = CallAudioStateCompat.ROUTE_WIRED_HEADSET;
         } else {
             if (mWasSpeakerOn) {
-                newRoute = CallAudioState.ROUTE_SPEAKER;
+                newRoute = CallAudioStateCompat.ROUTE_SPEAKER;
             } else {
-                newRoute = CallAudioState.ROUTE_EARPIECE;
+                newRoute = CallAudioStateCompat.ROUTE_EARPIECE;
             }
         }
 
-        mVoicemailPlaybackPresenter.setSpeakerphoneOn(newRoute == CallAudioState.ROUTE_SPEAKER);
+        mVoicemailPlaybackPresenter.setSpeakerphoneOn(newRoute == CallAudioStateCompat.ROUTE_SPEAKER);
 
         // We need to call this every time even if we do not change the route because the supported
         // routes changed either to include or not include WIRED_HEADSET.
         setSystemAudioState(
-                new CallAudioState(false /* muted */, newRoute, calculateSupportedRoutes()));
+                new CallAudioStateCompat(false /* muted */, newRoute, calculateSupportedRoutes()));
     }
 
     public void setSpeakerphoneOn(boolean on) {
-        setAudioRoute(on ? CallAudioState.ROUTE_SPEAKER : CallAudioState.ROUTE_WIRED_OR_EARPIECE);
+        setAudioRoute(on ? CallAudioStateCompat.ROUTE_SPEAKER
+                : CallAudioStateCompat.ROUTE_WIRED_OR_EARPIECE);
     }
 
     public boolean isWiredHeadsetPluggedIn() {
@@ -119,10 +120,10 @@
     /**
      * Change the audio route, for example from earpiece to speakerphone.
      *
-     * @param route The new audio route to use. See {@link CallAudioState}.
+     * @param route The new audio route to use. See {@link CallAudioStateCompat}.
      */
     void setAudioRoute(int route) {
-        Log.v(TAG, "setAudioRoute, route: " + CallAudioState.audioRouteToString(route));
+        Log.v(TAG, "setAudioRoute, route: " + CallAudioStateCompat.audioRouteToString(route));
 
         // Change ROUTE_WIRED_OR_EARPIECE to a single entry.
         int newRoute = selectWiredOrEarpiece(route, mCallAudioState.getSupportedRouteMask());
@@ -136,25 +137,25 @@
         if (mCallAudioState.getRoute() != newRoute) {
             // Remember the new speaker state so it can be restored when the user plugs and unplugs
             // a headset.
-            mWasSpeakerOn = newRoute == CallAudioState.ROUTE_SPEAKER;
-            setSystemAudioState(new CallAudioState(false /* muted */, newRoute,
+            mWasSpeakerOn = newRoute == CallAudioStateCompat.ROUTE_SPEAKER;
+            setSystemAudioState(new CallAudioStateCompat(false /* muted */, newRoute,
                     mCallAudioState.getSupportedRouteMask()));
         }
     }
 
-    private CallAudioState getInitialAudioState() {
+    private CallAudioStateCompat getInitialAudioState() {
         int supportedRouteMask = calculateSupportedRoutes();
-        int route = selectWiredOrEarpiece(CallAudioState.ROUTE_WIRED_OR_EARPIECE,
+        int route = selectWiredOrEarpiece(CallAudioStateCompat.ROUTE_WIRED_OR_EARPIECE,
                 supportedRouteMask);
-        return new CallAudioState(false /* muted */, route, supportedRouteMask);
+        return new CallAudioStateCompat(false /* muted */, route, supportedRouteMask);
     }
 
     private int calculateSupportedRoutes() {
-        int routeMask = CallAudioState.ROUTE_SPEAKER;
+        int routeMask = CallAudioStateCompat.ROUTE_SPEAKER;
         if (mWiredHeadsetManager.isPluggedIn()) {
-            routeMask |= CallAudioState.ROUTE_WIRED_HEADSET;
+            routeMask |= CallAudioStateCompat.ROUTE_WIRED_HEADSET;
         } else {
-            routeMask |= CallAudioState.ROUTE_EARPIECE;
+            routeMask |= CallAudioStateCompat.ROUTE_EARPIECE;
         }
         return routeMask;
     }
@@ -163,29 +164,29 @@
         // Since they are mutually exclusive and one is ALWAYS valid, we allow a special input of
         // ROUTE_WIRED_OR_EARPIECE so that callers don't have to make a call to check which is
         // supported before calling setAudioRoute.
-        if (route == CallAudioState.ROUTE_WIRED_OR_EARPIECE) {
-            route = CallAudioState.ROUTE_WIRED_OR_EARPIECE & supportedRouteMask;
+        if (route == CallAudioStateCompat.ROUTE_WIRED_OR_EARPIECE) {
+            route = CallAudioStateCompat.ROUTE_WIRED_OR_EARPIECE & supportedRouteMask;
             if (route == 0) {
                 Log.wtf(TAG, "One of wired headset or earpiece should always be valid.");
                 // assume earpiece in this case.
-                route = CallAudioState.ROUTE_EARPIECE;
+                route = CallAudioStateCompat.ROUTE_EARPIECE;
             }
         }
         return route;
     }
 
-    private void setSystemAudioState(CallAudioState callAudioState) {
-        CallAudioState oldAudioState = mCallAudioState;
+    private void setSystemAudioState(CallAudioStateCompat callAudioState) {
+        CallAudioStateCompat oldAudioState = mCallAudioState;
         mCallAudioState = callAudioState;
 
         Log.i(TAG, "setSystemAudioState: changing from " + oldAudioState + " to "
                 + mCallAudioState);
 
         // Audio route.
-        if (mCallAudioState.getRoute() == CallAudioState.ROUTE_SPEAKER) {
+        if (mCallAudioState.getRoute() == CallAudioStateCompat.ROUTE_SPEAKER) {
             turnOnSpeaker(true);
-        } else if (mCallAudioState.getRoute() == CallAudioState.ROUTE_EARPIECE ||
-                mCallAudioState.getRoute() == CallAudioState.ROUTE_WIRED_HEADSET) {
+        } else if (mCallAudioState.getRoute() == CallAudioStateCompat.ROUTE_EARPIECE ||
+                mCallAudioState.getRoute() == CallAudioStateCompat.ROUTE_WIRED_HEADSET) {
             // Just handle turning off the speaker, the system will handle switching between wired
             // headset and earpiece.
             turnOnSpeaker(false);