diff --git a/app/build.gradle b/app/build.gradle
index 4ad8776b..0f48622e 100644
--- a/app/build.gradle
+++ b/app/build.gradle
@@ -13,12 +13,12 @@ def getGitSha = { ->
 }
 
 android {
-    compileSdkVersion 27
-    buildToolsVersion '27.0.3'
+    compileSdkVersion 28
+    buildToolsVersion '28.0.2'
     defaultConfig {
         applicationId "com.keylesspalace.tusky"
         minSdkVersion 21
-        targetSdkVersion 27
+        targetSdkVersion 28
         versionCode 49
         versionName "3.1"
         testInstrumentationRunner "android.support.test.runner.AndroidJUnitRunner"
@@ -58,7 +58,7 @@ android {
     }
 }
 
-ext.supportLibraryVersion = '27.1.1'
+ext.supportLibraryVersion = '28.0.0-rc02'
 ext.daggerVersion = '2.17'
 
 
@@ -104,7 +104,7 @@ dependencies {
     implementation "com.google.dagger:dagger-android:$daggerVersion"
     implementation "com.google.dagger:dagger-android-support:$daggerVersion"
     kapt "com.google.dagger:dagger-android-processor:$daggerVersion"
-    testImplementation 'org.robolectric:robolectric:3.8'
+    testImplementation 'org.robolectric:robolectric:4.0-alpha-3'
     testImplementation 'org.mockito:mockito-inline:2.21.0'
     androidTestImplementation('com.android.support.test.espresso:espresso-core:3.0.1', {
         exclude group: 'com.android.support', module: 'support-annotations'
diff --git a/app/src/main/java/com/keylesspalace/tusky/di/AppInjector.kt b/app/src/main/java/com/keylesspalace/tusky/di/AppInjector.kt
index e78d352b..853f696b 100644
--- a/app/src/main/java/com/keylesspalace/tusky/di/AppInjector.kt
+++ b/app/src/main/java/com/keylesspalace/tusky/di/AppInjector.kt
@@ -68,7 +68,7 @@ object AppInjector {
         if (activity is FragmentActivity) {
             activity.supportFragmentManager.registerFragmentLifecycleCallbacks(
                     object : FragmentManager.FragmentLifecycleCallbacks() {
-                        override fun onFragmentCreated(fm: FragmentManager?, f: Fragment?,
+                        override fun onFragmentCreated(fm: FragmentManager, f: Fragment,
                                                        savedInstanceState: Bundle?) {
                             if (f is Injectable) {
                                 AndroidSupportInjection.inject(f)
diff --git a/app/src/main/java/com/keylesspalace/tusky/fragment/AccountMediaFragment.kt b/app/src/main/java/com/keylesspalace/tusky/fragment/AccountMediaFragment.kt
index 949a3f98..d3459bc9 100644
--- a/app/src/main/java/com/keylesspalace/tusky/fragment/AccountMediaFragment.kt
+++ b/app/src/main/java/com/keylesspalace/tusky/fragment/AccountMediaFragment.kt
@@ -174,7 +174,7 @@ class AccountMediaFragment : BaseFragment(), Injectable {
 
         recycler_view.addOnScrollListener(object : RecyclerView.OnScrollListener() {
 
-            override fun onScrolled(recycler_view: RecyclerView?, dx: Int, dy: Int) {
+            override fun onScrolled(recycler_view: RecyclerView, dx: Int, dy: Int) {
                 if (dy > 0) {
                     val itemCount = layoutManager.itemCount
                     val lastItem = layoutManager.findLastCompletelyVisibleItemPosition()
diff --git a/app/src/main/java/com/keylesspalace/tusky/view/ConversationLineItemDecoration.kt b/app/src/main/java/com/keylesspalace/tusky/view/ConversationLineItemDecoration.kt
index dc310e19..822ece56 100644
--- a/app/src/main/java/com/keylesspalace/tusky/view/ConversationLineItemDecoration.kt
+++ b/app/src/main/java/com/keylesspalace/tusky/view/ConversationLineItemDecoration.kt
@@ -26,7 +26,7 @@ import com.keylesspalace.tusky.adapter.ThreadAdapter
 
 class ConversationLineItemDecoration(private val context: Context, private val divider: Drawable) : RecyclerView.ItemDecoration() {
 
-    override fun onDraw(canvas: Canvas, parent: RecyclerView, state: RecyclerView.State?) {
+    override fun onDraw(canvas: Canvas, parent: RecyclerView, state: RecyclerView.State) {
         val dividerStart = parent.paddingStart + context.resources.getDimensionPixelSize(R.dimen.status_line_margin_start)
         val dividerEnd = dividerStart + divider.intrinsicWidth