upgrade Android Gradle Plugin to 3.5.4 to enable incremental compilation

build.gradle

@@ -8,8 +8,8 @@ buildscript {
 
     }
     dependencies {
-        classpath 'com.android.tools.build:gradle:3.4.1'
-        classpath 'com.google.gms:google-services:4.3.3'
+        classpath 'com.android.tools.build:gradle:3.5.4'
+        classpath 'com.google.gms:google-services:4.3.4'
  //       classpath 'me.tatarka:gradle-retrolambda:3.7.0'
 
         apply plugin: 'java'

gradle.properties

@@ -1,5 +1,20 @@
-# TODO we should lowercase the package names, see https://stackoverflow.com/questions/52495124/gradle-plugin-3-2-0-with-databinding-can-not-resolve-package-name
-android.databinding.enableV2=false
+# Using the AndroidX migration tool sets the following flags to true;
+# Requires Android Gradle plugin 3.2.0 and Gradle 4.6
+# When set to true, the Android plugin uses the appropriate AndroidX library instead of a Support Library.
+#android.useAndroidX=true
+# When set to true, the Android plugin automatically migrates existing third-party libraries to use
+# AndroidX by rewriting their binaries.
+#android.enableJetifier=true
+# enables incremental annotation processing, requires Android Gradle plugin 3.5.0 and Gradle 4.7
+android.databinding.incremental=true
+# generate the test config using relative paths, which allows the AndroidUnitTest task to be fully
+# cacheable, by including the following flag
+android.testConfig.useRelativePath=true
+# If, one or more annotation processors do not support incremental builds, incremental Java
+# compilation is not enabled. Instead, you can include the following flag and the Android Gradle
+# plugin executes the annotation processors in a separate task and allows the Java compilation task
+# to run incrementally. Requires Android Gradle plugin 3.3.0
+#android.enableSeparateAnnotationProcessing=true
 org.gradle.daemon=true
 org.gradle.caching=true
 org.gradle.parallel=true