app:theme replaced by android:theme in toolbar xml description. actionModeBackground removed.

app/src/main/res/drawable/myapp_action_mode_background.xml

-<?xml version="1.0" encoding="utf-8"?>
-<layer-list xmlns:android="http://schemas.android.com/apk/res/android">
-    <item android:top="-2dp" android:left="-2dp" android:right="-2dp">
-        <shape android:shape="rectangle">
-            <solid android:color="@color/primary_material_dark"/>
-        </shape>
-    </item>
-</layer-list>

app/src/main/res/layout/chat_viewer_item.xml

@@ -26,7 +26,7 @@
         android:layout_width="match_parent"
         android:minHeight="52dp"
 
-        app:theme="@style/ThemeOverlay.AppCompat.Dark.ActionBar"
+        android:theme="@style/ThemeOverlay.AppCompat.Dark.ActionBar"
         app:popupTheme="@style/ThemeOverlay.AppCompat.Light"
         android:background="?attr/colorPrimary"
         android:elevation="8dp"

app/src/main/res/layout/contact_subscription.xml

@@ -44,7 +44,7 @@
         android:id="@+id/top_toolbar"
         android:layout_width="match_parent"
         android:layout_height="?attr/actionBarSize"
-        app:theme="@style/ThemeOverlay.AppCompat.Dark.ActionBar"
+        android:theme="@style/ThemeOverlay.AppCompat.Dark.ActionBar"
         app:popupTheme="@style/ThemeOverlay.AppCompat.Light"
         android:elevation="8dp"
         android:background="@android:color/transparent"

app/src/main/res/layout/expandable_contact_title_activity.xml

@@ -33,7 +33,7 @@
         android:id="@+id/toolbar_overlay"
         android:layout_width="match_parent"
         android:layout_height="?attr/actionBarSize"
-        app:theme="@style/ThemeOverlay.AppCompat.Dark.ActionBar"
+        android:theme="@style/ThemeOverlay.AppCompat.Dark.ActionBar"
         app:popupTheme="@style/ThemeOverlay.AppCompat.Light"
         android:elevation="8dp"
         />

app/src/main/res/layout/toolbar_default.xml

@@ -7,7 +7,7 @@
     android:layout_width="match_parent"
     android:minHeight="?attr/actionBarSize"
 
-    app:theme="@style/ThemeOverlay.AppCompat.Dark.ActionBar"
+    android:theme="@style/ThemeOverlay.AppCompat.Dark.ActionBar"
     app:popupTheme="@style/ThemeOverlay.AppCompat.Light"
     android:background="?attr/colorPrimary"
     android:elevation="8dp"

app/src/main/res/values/theme.xml

@@ -19,8 +19,6 @@
 
         <!--for text selection toolbar to be above usual toolbar -->
         <item name="windowActionModeOverlay">true</item>
-        <!--for text selection toolbar color -->
-        <item name="actionModeBackground">@drawable/myapp_action_mode_background</item>
 
         <!-- for hardware button menu -->
         <item name="panelBackground">?attr/colorPrimary</item>