diff --git a/.idea/compiler.xml b/.idea/compiler.xml
index b589d56e9f..b86273d942 100644
--- a/.idea/compiler.xml
+++ b/.idea/compiler.xml
@@ -1,6 +1,6 @@
 <?xml version="1.0" encoding="UTF-8"?>
 <project version="4">
   <component name="CompilerConfiguration">
-    <bytecodeTargetLevel target="17" />
+    <bytecodeTargetLevel target="21" />
   </component>
 </project>
\ No newline at end of file
diff --git a/.semaphore/semaphore.yml b/.semaphore/semaphore.yml
index 2172e7a3a8..f80cd11f2a 100644
--- a/.semaphore/semaphore.yml
+++ b/.semaphore/semaphore.yml
@@ -39,8 +39,8 @@ global_job_config:
       # print some debug info
       - ping fel.localhost -c 1
       - ping fel.flowcrypt.test -c 1
-      # use JAVA 17 by default
-      - sem-version java 17
+      # use JAVA 21 by default
+      - sem-version java 21
       # general settings
       - export PATH=${ANDROID_HOME}/emulator:${ANDROID_HOME}/cmdline-tools/latest/bin:${ANDROID_HOME}/platform-tools:${PATH}
       - sudo rm -rf ~/.rbenv ~/.phpbrew
diff --git a/FlowCrypt/build.gradle.kts b/FlowCrypt/build.gradle.kts
index 8fdabed3c9..068dc18d9b 100644
--- a/FlowCrypt/build.gradle.kts
+++ b/FlowCrypt/build.gradle.kts
@@ -184,8 +184,8 @@ android {
 
   compileOptions {
     isCoreLibraryDesugaringEnabled = true
-    sourceCompatibility = JavaVersion.VERSION_17
-    targetCompatibility = JavaVersion.VERSION_17
+    sourceCompatibility = JavaVersion.VERSION_21
+    targetCompatibility = JavaVersion.VERSION_21
   }
 
   buildFeatures {
@@ -193,11 +193,6 @@ android {
     viewBinding = true
   }
 
-  kotlinOptions {
-    jvmTarget = JavaVersion.VERSION_17.toString()
-    freeCompilerArgs += listOf("-opt-in=kotlin.RequiresOptIn")
-  }
-
   packaging {
     resources.excludes += setOf(
       "META-INF/DEPENDENCIES",
@@ -328,6 +323,20 @@ easylauncher {
   }
 }
 
+java {
+  toolchain {
+    languageVersion.set(JavaLanguageVersion.of(21))
+  }
+}
+
+
+kotlin {
+  compilerOptions {
+    jvmTarget.set(org.jetbrains.kotlin.gradle.dsl.JvmTarget.JVM_21)
+    freeCompilerArgs.add("-opt-in=kotlin.RequiresOptIn")
+  }
+}
+
 tasks.register("checkCorrectBranch") {
   if (!grgit.branch.current().name.equals("master")) {
     throw GradleException("Please use 'master' branch to generate a release build")
@@ -436,7 +445,7 @@ dependencies {
   testImplementation("com.squareup.okhttp3:mockwebserver:5.1.0")
   testImplementation("com.flextrade.jfixture:jfixture:2.7.2")
   testImplementation("com.shazam:shazamcrest:0.11")
-  testImplementation("org.robolectric:robolectric:4.14.1")
+  testImplementation("org.robolectric:robolectric:4.16")
   //we need it to test Parcelable implementation
   testImplementation("org.jetbrains.kotlin:kotlin-reflect:2.2.10")
   testImplementation("junit:junit:4.13.2")