diff --git a/uhabits-android/build.gradle.kts b/uhabits-android/build.gradle.kts
index f215fe74a..dad64747a 100644
--- a/uhabits-android/build.gradle.kts
+++ b/uhabits-android/build.gradle.kts
@@ -27,13 +27,13 @@ plugins {
 }
 
 android {
-    compileSdkVersion(29)
+    compileSdkVersion(30)
 
     defaultConfig {
         versionCode(20001)
         versionName("2.0.1-alpha")
         minSdkVersion(23)
-        targetSdkVersion(29)
+        targetSdkVersion(30)
         applicationId("org.isoron.uhabits")
         testInstrumentationRunner("androidx.test.runner.AndroidJUnitRunner")
     }
diff --git a/uhabits-android/src/main/java/org/isoron/uhabits/activities/common/views/ScoreChart.kt b/uhabits-android/src/main/java/org/isoron/uhabits/activities/common/views/ScoreChart.kt
index 3a53f0f8a..f26e5374f 100644
--- a/uhabits-android/src/main/java/org/isoron/uhabits/activities/common/views/ScoreChart.kt
+++ b/uhabits-android/src/main/java/org/isoron/uhabits/activities/common/views/ScoreChart.kt
@@ -156,7 +156,7 @@ class ScoreChart : ScrollableChart {
                 drawMarker(activeCanvas, prevRect)
             }
             if (k == nColumns - 1) drawMarker(activeCanvas, rect)
-            prevRect!!.set(rect)
+            prevRect!!.set(rect!!)
             rect!![0f, 0f, columnWidth] = columnHeight.toFloat()
             rect!!.offset(k * columnWidth, internalPaddingTop.toFloat())
             drawFooter(activeCanvas, rect, timestamp)
diff --git a/uhabits-android/src/main/java/org/isoron/uhabits/activities/settings/SettingsFragment.kt b/uhabits-android/src/main/java/org/isoron/uhabits/activities/settings/SettingsFragment.kt
index 4187f5008..042ec2777 100644
--- a/uhabits-android/src/main/java/org/isoron/uhabits/activities/settings/SettingsFragment.kt
+++ b/uhabits-android/src/main/java/org/isoron/uhabits/activities/settings/SettingsFragment.kt
@@ -147,7 +147,7 @@ class SettingsFragment : PreferenceFragmentCompat(), OnSharedPreferenceChangeLis
 
     override fun onSharedPreferenceChanged(
         sharedPreferences: SharedPreferences,
-        key: String
+        key: String?
     ) {
         if (key == "pref_widget_opacity" && widgetUpdater != null) {
             Log.d("SettingsFragment", "updating widgets")
diff --git a/uhabits-android/src/main/java/org/isoron/uhabits/notifications/SnoozeDelayPickerActivity.kt b/uhabits-android/src/main/java/org/isoron/uhabits/notifications/SnoozeDelayPickerActivity.kt
index ace88e61d..3ec9caa2c 100644
--- a/uhabits-android/src/main/java/org/isoron/uhabits/notifications/SnoozeDelayPickerActivity.kt
+++ b/uhabits-android/src/main/java/org/isoron/uhabits/notifications/SnoozeDelayPickerActivity.kt
@@ -45,12 +45,16 @@ class SnoozeDelayPickerActivity : FragmentActivity(), OnItemClickListener {
         super.onCreate(bundle)
         val intent = intent
         if (intent == null) finish()
-        if (intent.data == null) finish()
         val app = applicationContext as HabitsApplication
         val appComponent = app.component
-        reminderController = appComponent.reminderController
-        habit = appComponent.habitList.getById(ContentUris.parseId(intent.data))
+        val data = intent.data
+        if (data == null) {
+            finish()
+        } else {
+            habit = appComponent.habitList.getById(ContentUris.parseId(data))
+        }
         if (habit == null) finish()
+        reminderController = appComponent.reminderController
         val theme = R.style.Theme_AppCompat_Light_Dialog_Alert
         dialog = AlertDialog.Builder(ContextThemeWrapper(this, theme))
             .setTitle(R.string.select_snooze_delay)
diff --git a/uhabits-android/src/main/java/org/isoron/uhabits/preferences/SharedPreferencesStorage.kt b/uhabits-android/src/main/java/org/isoron/uhabits/preferences/SharedPreferencesStorage.kt
index 279357858..febc7f976 100644
--- a/uhabits-android/src/main/java/org/isoron/uhabits/preferences/SharedPreferencesStorage.kt
+++ b/uhabits-android/src/main/java/org/isoron/uhabits/preferences/SharedPreferencesStorage.kt
@@ -79,7 +79,7 @@ class SharedPreferencesStorage
 
     override fun onSharedPreferenceChanged(
         sharedPreferences: SharedPreferences,
-        key: String
+        key: String?
     ) {
         val preferences = this.preferences ?: return
         sharedPreferences.unregisterOnSharedPreferenceChangeListener(this)
diff --git a/uhabits-android/src/main/java/org/isoron/uhabits/receivers/ReminderReceiver.kt b/uhabits-android/src/main/java/org/isoron/uhabits/receivers/ReminderReceiver.kt
index 026f99bec..951b46ae8 100644
--- a/uhabits-android/src/main/java/org/isoron/uhabits/receivers/ReminderReceiver.kt
+++ b/uhabits-android/src/main/java/org/isoron/uhabits/receivers/ReminderReceiver.kt
@@ -46,7 +46,8 @@ class ReminderReceiver : BroadcastReceiver() {
         Log.i(TAG, String.format("Received intent: %s", intent.toString()))
         var habit: Habit? = null
         val today: Long = getStartOfTodayWithOffset()
-        if (intent.data != null) habit = habits.getById(ContentUris.parseId(intent.data))
+        val data = intent.data
+        if (data != null) habit = habits.getById(ContentUris.parseId(data))
         val timestamp = intent.getLongExtra("timestamp", today)
         val reminderTime = intent.getLongExtra("reminderTime", today)
         try {