diff --git a/app/src/main/java/com/nextcloud/talk/activities/CallActivity.kt b/app/src/main/java/com/nextcloud/talk/activities/CallActivity.kt
index 00c6187549b..8988006e512 100644
--- a/app/src/main/java/com/nextcloud/talk/activities/CallActivity.kt
+++ b/app/src/main/java/com/nextcloud/talk/activities/CallActivity.kt
@@ -455,6 +455,10 @@ class CallActivity : CallBaseActivity() {
         processExtras(intent.extras!!)
         conversationUser = currentUserProviderOld.currentUser.blockingGet()
 
+        if (warnAndFinishIfCallEndToEndEncryptionUnsupported()) {
+            return
+        }
+
         credentials = ApiUtils.getCredentials(conversationUser!!.username, conversationUser!!.token)
         if (TextUtils.isEmpty(baseUrl)) {
             baseUrl = conversationUser!!.baseUrl
@@ -477,6 +481,15 @@ class CallActivity : CallBaseActivity() {
         checkInitialDevicePermissions()
     }
 
+    private fun warnAndFinishIfCallEndToEndEncryptionUnsupported(): Boolean {
+        if (!CapabilitiesUtil.isCallEndToEndEncryptionEnabled(conversationUser?.capabilities?.spreedCapability)) {
+            return false
+        }
+        Toast.makeText(context, R.string.nc_call_e2ee_not_supported, Toast.LENGTH_LONG).show()
+        finish()
+        return true
+    }
+
     private fun initCallRecordingViewModel(recordingState: Int) {
         callRecordingViewModel = ViewModelProvider(this, viewModelFactory).get(
             CallRecordingViewModel::class.java
diff --git a/app/src/main/java/com/nextcloud/talk/callnotification/CallNotificationActivity.kt b/app/src/main/java/com/nextcloud/talk/callnotification/CallNotificationActivity.kt
index aaad05b3aef..abcd3d9d022 100644
--- a/app/src/main/java/com/nextcloud/talk/callnotification/CallNotificationActivity.kt
+++ b/app/src/main/java/com/nextcloud/talk/callnotification/CallNotificationActivity.kt
@@ -15,6 +15,7 @@ import android.os.Handler
 import android.os.Looper
 import android.util.Log
 import android.view.View
+import android.widget.Toast
 import androidx.core.app.NotificationManagerCompat
 import autodagger.AutoInjector
 import com.nextcloud.talk.R
@@ -29,6 +30,7 @@ import com.nextcloud.talk.extensions.loadUserAvatar
 import com.nextcloud.talk.models.json.participants.Participant
 import com.nextcloud.talk.users.UserManager
 import com.nextcloud.talk.utils.ApiUtils
+import com.nextcloud.talk.utils.CapabilitiesUtil
 import com.nextcloud.talk.utils.CapabilitiesUtil.hasSpreedFeatureCapability
 import com.nextcloud.talk.utils.NotificationUtils
 import com.nextcloud.talk.utils.SpreedFeatures
@@ -190,6 +192,11 @@ class CallNotificationActivity : CallBaseActivity() {
     }
 
     private fun proceedToCall() {
+        if (CapabilitiesUtil.isCallEndToEndEncryptionEnabled(userBeingCalled?.capabilities?.spreedCapability)) {
+            Toast.makeText(context, R.string.nc_call_e2ee_not_supported, Toast.LENGTH_LONG).show()
+            hangup()
+            return
+        }
         val callIntent = Intent(this, CallActivity::class.java)
         intent.putExtra(KEY_ROOM_ONE_TO_ONE, isOneToOneCall)
         callIntent.putExtras(intent.extras!!)
diff --git a/app/src/main/java/com/nextcloud/talk/chat/ChatActivity.kt b/app/src/main/java/com/nextcloud/talk/chat/ChatActivity.kt
index 0b174c37857..71a21eaaa15 100644
--- a/app/src/main/java/com/nextcloud/talk/chat/ChatActivity.kt
+++ b/app/src/main/java/com/nextcloud/talk/chat/ChatActivity.kt
@@ -3437,6 +3437,10 @@ class ChatActivity :
     private fun startACall(isVoiceOnlyCall: Boolean, callWithoutNotification: Boolean) {
         currentConversation?.let {
             if (::conversationUser.isInitialized) {
+                if (CapabilitiesUtil.isCallEndToEndEncryptionEnabled(spreedCapabilities)) {
+                    Snackbar.make(binding.root, R.string.nc_call_e2ee_not_supported, Snackbar.LENGTH_LONG).show()
+                    return
+                }
                 val pp = ParticipantPermissions(spreedCapabilities, it)
                 if (!pp.canStartCall() && currentConversation?.hasCall == false) {
                     Snackbar.make(binding.root, R.string.startCallForbidden, Snackbar.LENGTH_LONG).show()
diff --git a/app/src/main/java/com/nextcloud/talk/chat/MessageInputFragment.kt b/app/src/main/java/com/nextcloud/talk/chat/MessageInputFragment.kt
index 51dc3d0c75c..220b95633a1 100644
--- a/app/src/main/java/com/nextcloud/talk/chat/MessageInputFragment.kt
+++ b/app/src/main/java/com/nextcloud/talk/chat/MessageInputFragment.kt
@@ -37,7 +37,6 @@ import android.widget.RelativeLayout
 import android.widget.SeekBar
 import androidx.appcompat.view.ContextThemeWrapper
 import androidx.compose.material3.MaterialTheme
-import androidx.core.content.ContextCompat
 import androidx.core.graphics.drawable.toDrawable
 import androidx.core.view.isVisible
 import androidx.core.widget.doAfterTextChanged
diff --git a/app/src/main/java/com/nextcloud/talk/conversationlist/ConversationsListActivity.kt b/app/src/main/java/com/nextcloud/talk/conversationlist/ConversationsListActivity.kt
index 059bba60338..006ebcf55e9 100644
--- a/app/src/main/java/com/nextcloud/talk/conversationlist/ConversationsListActivity.kt
+++ b/app/src/main/java/com/nextcloud/talk/conversationlist/ConversationsListActivity.kt
@@ -1100,6 +1100,10 @@ class ConversationsListActivity : BaseActivity() {
             chatIntent.putExtras(bundle)
 
             if (currentUser != null) {
+                if (CapabilitiesUtil.isCallEndToEndEncryptionEnabled(currentUser?.capabilities?.spreedCapability)) {
+                    showSnackbar(context.getString(R.string.nc_call_e2ee_not_supported))
+                    return@let
+                }
                 val pp = ParticipantPermissions(currentUser?.capabilities?.spreedCapability, it)
                 if (!pp.canStartCall() && selectedConversation?.hasCall == false) {
                     Log.e(TAG, "Error starting call from conversations list: call is forbidden")
diff --git a/app/src/main/java/com/nextcloud/talk/jobs/NotificationWorker.kt b/app/src/main/java/com/nextcloud/talk/jobs/NotificationWorker.kt
index 86cb13d8388..4358cf0d83d 100644
--- a/app/src/main/java/com/nextcloud/talk/jobs/NotificationWorker.kt
+++ b/app/src/main/java/com/nextcloud/talk/jobs/NotificationWorker.kt
@@ -76,6 +76,7 @@ import com.nextcloud.talk.receivers.ShareRecordingToChatReceiver
 import com.nextcloud.talk.users.UserManager
 import com.nextcloud.talk.utils.ActorAvatar
 import com.nextcloud.talk.utils.ApiUtils
+import com.nextcloud.talk.utils.CapabilitiesUtil
 import com.nextcloud.talk.utils.CharacterAvatarUtils
 import com.nextcloud.talk.utils.ConversationUtils
 import com.nextcloud.talk.utils.DisplayUtils
@@ -404,7 +405,14 @@ class NotificationWorker(context: Context, workerParams: WorkerParameters) : Wor
 
                 override fun onNext(conversation: ConversationModel) {
                     if (userManager.setUserAsActive(userBeingCalled!!).blockingGet()) {
-                        prepareCallNotificationScreen(conversation)
+                        if (CapabilitiesUtil.isCallEndToEndEncryptionEnabled(
+                                userBeingCalled?.capabilities?.spreedCapability
+                            )
+                        ) {
+                            showEndToEndEncryptionUnsupportedNotification(conversation)
+                        } else {
+                            prepareCallNotificationScreen(conversation)
+                        }
                     }
                 }
 
@@ -1299,6 +1307,34 @@ class NotificationWorker(context: Context, workerParams: WorkerParameters) : Wor
         }
     }
 
+    private fun showEndToEndEncryptionUnsupportedNotification(conversation: ConversationModel) {
+        val notificationBuilder = NotificationCompat.Builder(
+            context!!,
+            NotificationUtils.NotificationChannels
+                .NOTIFICATION_CHANNEL_MESSAGES_V4.name
+        )
+
+        val intent = createMainActivityIntent()
+
+        val notification: Notification = notificationBuilder
+            .setContentTitle(
+                String.format(
+                    context!!.resources.getString(R.string.nc_call_e2ee_not_supported_title),
+                    conversation.displayName
+                )
+            )
+            .setContentText(context!!.resources.getString(R.string.nc_call_e2ee_not_supported))
+            .setSmallIcon(R.drawable.ic_call_black_24dp)
+            .setOngoing(false)
+            .setAutoCancel(true)
+            .setPriority(NotificationCompat.PRIORITY_LOW)
+            .setContentIntent(createUniquePendingIntent(intent))
+            .build()
+
+        sendNotification(pushMessage.timestamp.toInt(), notification)
+        Log.d(TAG, "'end-to-end-encryption not supported' notification was created for ${conversation.token}")
+    }
+
     private fun createMainActivityIntent(): Intent {
         val intent = Intent(context, MainActivity::class.java)
         intent.flags = getIntentFlags()
diff --git a/app/src/main/java/com/nextcloud/talk/utils/CapabilitiesUtil.kt b/app/src/main/java/com/nextcloud/talk/utils/CapabilitiesUtil.kt
index 5448fbed8dc..04ab84f0359 100644
--- a/app/src/main/java/com/nextcloud/talk/utils/CapabilitiesUtil.kt
+++ b/app/src/main/java/com/nextcloud/talk/utils/CapabilitiesUtil.kt
@@ -327,6 +327,17 @@ object CapabilitiesUtil {
     fun isBanningAvailable(spreedCapabilities: SpreedCapability): Boolean =
         hasSpreedFeatureCapability(spreedCapabilities, SpreedFeatures.BAN_V1)
 
+    fun isCallEndToEndEncryptionEnabled(spreedCapabilities: SpreedCapability?): Boolean {
+        if (
+            spreedCapabilities?.config?.containsKey("call") == true &&
+            spreedCapabilities.config!!["call"] != null &&
+            spreedCapabilities.config!!["call"]!!.containsKey("end-to-end-encryption")
+        ) {
+            return spreedCapabilities.config!!["call"]!!["end-to-end-encryption"].toString().toBoolean()
+        }
+        return false
+    }
+
     // endregion
 
     //region SpreedCapabilities that can't be used with federation as the settings for them are global
diff --git a/app/src/main/res/values/strings.xml b/app/src/main/res/values/strings.xml
index 9daacee5f3e..85b4dadbfbc 100644
--- a/app/src/main/res/values/strings.xml
+++ b/app/src/main/res/values/strings.xml
@@ -641,6 +641,8 @@ How to translate with transifex:
     <string name="nc_keep">Keep</string>
     <string name="nc_delete_message_leaked_to_matterbridge">Message deleted successfully, but it might have been leaked to other services</string>
     <string name="startCallForbidden">You are not allowed to start a call</string>
+    <string name="nc_call_e2ee_not_supported_title">Call from %s unavailable</string>
+    <string name="nc_call_e2ee_not_supported">Calling is currently not supported because end-to-end encryption is enabled on the server</string>
     <string name="nc_last_moderator_leaving_room_warning">You need to promote a new moderator before you can leave the conversation</string>
     <string name="nc_room_retention">Room is retained successfully</string>