--- a/build.gradle
+++ b/build.gradle
@@ -46,17 +46,17 @@ buildscript {
         }
         // For in tree plugins.
         maven {
             url "file://${gradle.mozconfig.topsrcdir}/mobile/android/gradle/m2repo"
         }
     }
 
     ext.kotlin_version = '1.2.41'
-    ext.support_library_version = '23.4.0'
+    ext.support_library_version = '26.1.0'
 
     if (gradle.mozconfig.substs.MOZ_ANDROID_GOOGLE_PLAY_SERVICES) {
         ext.google_play_services_version = '8.4.0'
     }
 
     dependencies {
         classpath 'com.android.tools.build:gradle:3.0.1'
         classpath 'com.getkeepsafe.dexcount:dexcount-gradle-plugin:0.8.2'

--- a/mobile/android/app/src/main/res/layout/bookmark_add_folder.xml
+++ b/mobile/android/app/src/main/res/layout/bookmark_add_folder.xml
@@ -13,17 +13,17 @@
     android:background="@android:color/white">
 
     <android.support.v7.widget.Toolbar
         android:id="@+id/toolbar"
         android:layout_width="match_parent"
         android:layout_height="?actionBarSize"
         android:theme="@style/ThemeOverlay.AppCompat.Dark.ActionBar"
         android:background="@color/text_and_tabs_tray_grey"
-        app:navigationIcon="@drawable/abc_ic_clear_mtrl_alpha"
+        app:navigationIcon="@drawable/abc_ic_clear_material"
         app:subtitleTextColor="@android:color/white"
         app:title="@string/bookmark_add_folder"
         app:titleTextColor="@android:color/white" />
 
     <LinearLayout
         android:layout_width="match_parent"
         android:layout_height="0dp"
         android:layout_weight="1"

--- a/mobile/android/app/src/main/res/layout/bookmark_edit_with_full_page.xml
+++ b/mobile/android/app/src/main/res/layout/bookmark_edit_with_full_page.xml
@@ -13,17 +13,17 @@
 
     <android.support.v7.widget.Toolbar
         android:id="@+id/toolbar"
         android:layout_width="match_parent"
         android:layout_height="56dp"
         android:theme="@style/ThemeOverlay.AppCompat.Dark.ActionBar"
         android:background="@color/text_and_tabs_tray_grey"
         android:minHeight="?actionBarSize"
-        app:navigationIcon="@drawable/abc_ic_clear_mtrl_alpha"
+        app:navigationIcon="@drawable/abc_ic_clear_material"
         app:subtitleTextColor="@android:color/white"
         app:titleTextColor="@android:color/white" />
 
     <ScrollView
         android:layout_width="match_parent"
         android:layout_height="match_parent">
 
         <LinearLayout

--- a/mobile/android/app/src/main/res/layout/bookmark_folder_select.xml
+++ b/mobile/android/app/src/main/res/layout/bookmark_folder_select.xml
@@ -12,17 +12,17 @@
     android:background="@android:color/white">
 
     <android.support.v7.widget.Toolbar
         android:id="@+id/toolbar"
         android:layout_width="match_parent"
         android:layout_height="?actionBarSize"
         android:theme="@style/ThemeOverlay.AppCompat.Dark.ActionBar"
         android:background="@color/text_and_tabs_tray_grey"
-        app:navigationIcon="@drawable/abc_ic_ab_back_mtrl_am_alpha"
+        app:navigationIcon="@drawable/abc_ic_ab_back_material"
         app:subtitleTextColor="@android:color/white"
         app:title="@string/bookmark_select_folder" />
 
     <android.support.v7.widget.RecyclerView
         android:id="@+id/folder_recycler_view"
         android:layout_width="match_parent"
         android:layout_height="0dp"
         android:layout_weight="1"

--- a/mobile/android/base/java/org/mozilla/gecko/customtabs/GeckoCustomTabsService.java
+++ b/mobile/android/base/java/org/mozilla/gecko/customtabs/GeckoCustomTabsService.java
@@ -98,9 +98,19 @@ public class GeckoCustomTabsService exte
     }
 
     @Override
     protected Bundle extraCommand(String commandName, Bundle bundle) {
         Log.v(LOGTAG, "extraCommand()");
 
         return null;
     }
+
+    @Override
+    protected boolean requestPostMessageChannel(CustomTabsSessionToken sessionToken, Uri postMessageOrigin) {
+        return false;
+    }
+
+    @Override
+    protected int postMessage(CustomTabsSessionToken sessionToken, String message, Bundle extras) {
+        return RESULT_FAILURE_DISALLOWED;
+    }
 }

--- a/mobile/android/base/java/org/mozilla/gecko/preferences/GeckoPreferences.java
+++ b/mobile/android/base/java/org/mozilla/gecko/preferences/GeckoPreferences.java
@@ -226,17 +226,17 @@ public class GeckoPreferences
         }
     }
 
     private void updateHomeAsUpIndicator() {
         final ActionBar actionBar = getSupportActionBar();
         if (actionBar == null) {
             return;
         }
-        actionBar.setHomeAsUpIndicator(android.support.v7.appcompat.R.drawable.abc_ic_ab_back_mtrl_am_alpha);
+        actionBar.setHomeAsUpIndicator(android.support.v7.appcompat.R.drawable.abc_ic_ab_back_material);
     }
 
     /**
      * We only call this method for pre-HC versions of Android.
      */
     private void updateTitleForPrefsResource(int res) {
         // At present we only need to do this for non-leaf prefs views
         // and the locale switcher itself.

--- a/mobile/android/base/java/org/mozilla/gecko/widget/DefaultItemAnimatorBase.java
+++ b/mobile/android/base/java/org/mozilla/gecko/widget/DefaultItemAnimatorBase.java
@@ -1,17 +1,18 @@
 /* -*- Mode: Java; c-basic-offset: 4; tab-width: 20; indent-tabs-mode: nil; -*-
  * This Source Code Form is subject to the terms of the Mozilla Public
  * License, v. 2.0. If a copy of the MPL was not distributed with this
  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
 
 package org.mozilla.gecko.widget;
 
+import android.animation.TimeInterpolator;
+import android.animation.ValueAnimator;
 import android.support.annotation.NonNull;
-import android.support.v4.animation.AnimatorCompatHelper;
 import android.support.v4.view.ViewCompat;
 import android.support.v4.view.ViewPropertyAnimatorCompat;
 import android.support.v4.view.ViewPropertyAnimatorListener;
 import android.support.v7.widget.RecyclerView;
 import android.support.v7.widget.SimpleItemAnimator;
 import android.view.View;
 
 import java.util.ArrayList;
@@ -36,16 +37,18 @@ import java.util.List;
  *       values before resetting the current animation, so this class does not provide the reset
  *       service itself.</li>
  *   <li>{@link #resetViewProperties(View)} is used to reset a view any time an animation ends or
  *       gets canceled - you should redefine resetViewProperties if the version here doesn't reset
  *       all of the properties you're animating.</li>
  * </ul>
  */
 public class DefaultItemAnimatorBase extends SimpleItemAnimator {
+    private static TimeInterpolator defaultInterpolator;
+
     private List<RecyclerView.ViewHolder> pendingRemovals = new ArrayList<>();
     private List<RecyclerView.ViewHolder> pendingAdditions = new ArrayList<>();
     private List<MoveInfo> pendingMoves = new ArrayList<>();
     private List<ChangeInfo> pendingChanges = new ArrayList<>();
 
     private List<List<RecyclerView.ViewHolder>> additionsList = new ArrayList<>();
     private List<List<MoveInfo>> movesList = new ArrayList<>();
     private List<List<ChangeInfo>> changesList = new ArrayList<>();
@@ -476,17 +479,20 @@ public class DefaultItemAnimatorBase ext
                     additionsList.remove(i);
                 }
             }
         }
         dispatchFinishedWhenDone();
     }
 
     protected void resetAnimation(RecyclerView.ViewHolder holder) {
-        AnimatorCompatHelper.clearInterpolator(holder.itemView);
+        if (defaultInterpolator == null) {
+            defaultInterpolator = new ValueAnimator().getInterpolator();
+        }
+        holder.itemView.animate().setInterpolator(defaultInterpolator);
         endAnimation(holder);
     }
 
     @Override
     public boolean isRunning() {
         return (!pendingAdditions.isEmpty() ||
                 !pendingChanges.isEmpty() ||
                 !pendingMoves.isEmpty() ||

deleted file mode 100644
--- a/mobile/android/thirdparty/com/leanplum/activities/LeanplumActionBarActivity.java
+++ /dev/null
@@ -1,77 +0,0 @@
-/*
- * Copyright 2013, Leanplum, Inc. All rights reserved.
- *
- * Licensed to the Apache Software Foundation (ASF) under one
- * or more contributor license agreements.  See the NOTICE file
- * distributed with this work for additional information
- * regarding copyright ownership.  The ASF licenses this file
- * to you 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.leanplum.activities;
-
-import android.annotation.SuppressLint;
-import android.content.res.Resources;
-import android.support.v7.app.ActionBarActivity;
-
-import com.leanplum.Leanplum;
-import com.leanplum.LeanplumActivityHelper;
-
-@SuppressLint("Registered")
-@SuppressWarnings("deprecation")
-public class LeanplumActionBarActivity extends ActionBarActivity {
-  private LeanplumActivityHelper helper;
-
-  private LeanplumActivityHelper getHelper() {
-    if (helper == null) {
-      helper = new LeanplumActivityHelper(this);
-    }
-    return helper;
-  }
-
-  @Override
-  protected void onPause() {
-    super.onPause();
-    getHelper().onPause();
-  }
-
-  @Override
-  protected void onStop() {
-    super.onStop();
-    getHelper().onStop();
-  }
-
-  @Override
-  protected void onResume() {
-    super.onResume();
-    getHelper().onResume();
-  }
-
-  @Override
-  public Resources getResources() {
-    if (Leanplum.isTestModeEnabled() || !Leanplum.isResourceSyncingEnabled()) {
-      return super.getResources();
-    }
-    return getHelper().getLeanplumResources(super.getResources());
-  }
-
-  @Override
-  public void setContentView(final int layoutResID) {
-    if (Leanplum.isTestModeEnabled() || !Leanplum.isResourceSyncingEnabled()) {
-      super.setContentView(layoutResID);
-      return;
-    }
-    getHelper().setContentView(layoutResID);
-  }
-}