diff --git a/.github/workflows/build.yml b/.github/workflows/build.yml
index 0c7a7443..75ef2314 100644
--- a/.github/workflows/build.yml
+++ b/.github/workflows/build.yml
@@ -31,11 +31,11 @@ jobs:
       with:
         submodules: true
 
-    - name: Set up Java 17
-      uses: actions/setup-java@v2
+    - name: Set up Java 21
+      uses: actions/setup-java@v4
       with:
-        distribution: 'adopt'
-        java-version: '17'
+        distribution: 'temurin'
+        java-version: '21'
 
     - name: Test Bash Keystores scripts
       run: make test-bash-keystore
@@ -85,11 +85,11 @@ jobs:
       with:
         submodules: true
 
-    - name: Set up Java 17
-      uses: actions/setup-java@v2
+    - name: Set up Java 21
+      uses: actions/setup-java@v4
       with:
-        distribution: 'adopt'
-        java-version: '17'
+        distribution: 'temurin'
+        java-version: '21'
 
     - name: Enable KVM
       run: |
diff --git a/.github/workflows/publish.yml b/.github/workflows/publish.yml
index 602a5882..b8755ee5 100644
--- a/.github/workflows/publish.yml
+++ b/.github/workflows/publish.yml
@@ -22,11 +22,11 @@ jobs:
     - name: Set release version
       run: echo "RELEASE_VERSION=${GITHUB_REF#refs/*/}" >> $GITHUB_ENV
 
-    - name: Set up Java 17
-      uses: actions/setup-java@v2
+    - name: Set up Java 21
+      uses: actions/setup-java@v4
       with:
-        distribution: 'adopt'
-        java-version: '17'
+        distribution: 'temurin'
+        java-version: '21'
 
     - name: Set up Ruby
       uses: ruby/setup-ruby@v1
diff --git a/build.gradle b/build.gradle
index 524f786b..ec8e0c0d 100644
--- a/build.gradle
+++ b/build.gradle
@@ -99,9 +99,14 @@ def getVersionCode = {
 def getVersionName = {
   System.env.RELEASE_VERSION ?: 'SNAPSHOT'
 }
-
+java {
+  // Pins the JDK used to compile
+  toolchain {
+    languageVersion = JavaLanguageVersion.of(21)
+  }
+}
 android {
-  compileSdk 35
+  compileSdk 36
   packagingOptions {
     resources {
       excludes += ['META-INF/LICENSE', 'META-INF/NOTICE']
@@ -114,7 +119,7 @@ android {
 
   defaultConfig {
     //noinspection OldTargetApi
-    targetSdkVersion 35
+    targetSdkVersion 36
     minSdkVersion 21 // Android 5.0
     versionCode getVersionCode()
     versionName getVersionName()
@@ -496,9 +501,9 @@ dependencies {
   compileOnly 'com.github.spotbugs:spotbugs-annotations:4.9.3'
   coreLibraryDesugaring 'com.android.tools:desugar_jdk_libs:2.1.5'
   testImplementation 'junit:junit:4.13.2'
-  testImplementation 'org.mockito:mockito-inline:5.2.0'
+  testImplementation 'org.mockito:mockito-core:5.23.0'
   testImplementation 'com.google.android:android-test:4.1.1.4'
-  testImplementation 'org.robolectric:robolectric:4.15.1'
+  testImplementation 'org.robolectric:robolectric:4.16.1'
   testImplementation 'androidx.test.espresso:espresso-core:3.7.0'
   testImplementation 'androidx.test.espresso:espresso-intents:3.7.0'
   testImplementation 'androidx.test.ext:junit:1.3.0'
diff --git a/src/main/AndroidManifest.xml b/src/main/AndroidManifest.xml
index 20c4e672..336facce 100644
--- a/src/main/AndroidManifest.xml
+++ b/src/main/AndroidManifest.xml
@@ -33,6 +33,7 @@
       android:fullBackupContent="@xml/backup_rules_sdk_30_and_lower"
       android:dataExtractionRules="@xml/backup_rules"
       android:largeHeap="true"
+      android:enableOnBackInvokedCallback="false"
       tools:ignore="LockedOrientationActivity,UnusedAttribute">
     <activity android:name="StartupActivity" android:exported="true">
       <intent-filter>
diff --git a/src/test/java/org/medicmobile/webapp/mobile/SmsSenderTest.java b/src/test/java/org/medicmobile/webapp/mobile/SmsSenderTest.java
index 1c3f5cea..01af6ece 100644
--- a/src/test/java/org/medicmobile/webapp/mobile/SmsSenderTest.java
+++ b/src/test/java/org/medicmobile/webapp/mobile/SmsSenderTest.java
@@ -21,6 +21,7 @@
 import android.app.PendingIntent;
 import android.content.Context;
 import android.content.Intent;
+import android.os.Build;
 import android.telephony.SmsManager;
 
 import androidx.core.content.ContextCompat;
@@ -39,6 +40,7 @@
 import org.mockito.quality.Strictness;
 import org.robolectric.RobolectricTestRunner;
 import org.robolectric.annotation.Config;
+import org.robolectric.util.ReflectionHelpers;
 
 import java.util.ArrayList;
 import java.util.Arrays;
@@ -76,6 +78,21 @@ public void setup() {
 		smsSender = SmsSender.createInstance(parentMock);
 	}
 
+	/**
+	 * Robolectric no longer emulates SDK < 23, so tests covering the pre-M code
+	 * path (still reachable with minSdkVersion 21) have to force SDK_INT instead
+	 * of using {@code @Config(sdk = 22)}.
+	 */
+	private void withSdkInt(int sdkInt, Runnable body) {
+		int originalSdkInt = Build.VERSION.SDK_INT;
+		ReflectionHelpers.setStaticField(Build.VERSION.class, "SDK_INT", sdkInt);
+		try {
+			body.run();
+		} finally {
+			ReflectionHelpers.setStaticField(Build.VERSION.class, "SDK_INT", originalSdkInt);
+		}
+	}
+
 	@Test
 	public void createInstance() {
 		assertEquals(SmsSender.class, smsSender.getClass());
@@ -88,9 +105,8 @@ public void createInstance_RSmsSender() {
 	}
 
 	@Test
-	@Config(sdk = 22)
 	public void createInstance_LSmsSender() {
-		assertEquals(SmsSender.LSmsSender.class, smsSender.getClass());
+		withSdkInt(22, () -> assertEquals(SmsSender.LSmsSender.class, SmsSender.createInstance(parentMock).getClass()));
 	}
 
 	@Test
@@ -165,7 +181,6 @@ public void send_withPermissions_sendsMultipartTextMessage_RSmsSender() {
 	}
 
 	@Test
-	@Config(sdk = 22)
 	public void send_withPermissions_sendsMultipartTextMessage_LSmsSender() {
 		try (
 			MockedStatic<ContextCompat> contextCompatMock = mockStatic(ContextCompat.class);
@@ -173,6 +188,7 @@ public void send_withPermissions_sendsMultipartTextMessage_LSmsSender() {
 			MockedStatic<PendingIntent> pendingIntentMock = mockStatic(PendingIntent.class)
 		) {
 			//> GIVEN
+			withSdkInt(22, () -> smsSender = SmsSender.createInstance(parentMock));
 			contextCompatMock.when(() -> ContextCompat.checkSelfPermission(eq(parentMock), eq(SEND_SMS))).thenReturn(PERMISSION_GRANTED);
 			int expectedBroadcastFlags = FLAG_ONE_SHOT;
 			mockGetBroadcast(pendingIntentMock, expectedBroadcastFlags);