diff --git a/lib/components/peer-olm-session-creator-provider.react.js b/lib/components/peer-olm-session-creator-provider.react.js
--- a/lib/components/peer-olm-session-creator-provider.react.js
+++ b/lib/components/peer-olm-session-creator-provider.react.js
@@ -45,7 +45,6 @@
 
   const deadDevices = useSelector(getPeersDeadDeviceIDs);
   const refetchDeviceList = useGetAndUpdateDeviceListsForUsers();
-  const auxUserInfos = useSelector(state => state.auxUserStore.auxUserInfos);
 
   const createOlmSessionsWithUserCallback = React.useCallback(
     async (
@@ -57,20 +56,11 @@
         runningPromises.current[userID] = {};
       }
 
-      const filteredDevices = devices
-        .filter(
-          request =>
-            !runningPromises.current[userID][request.deviceID] &&
-            !deadDevices.has(request.deviceID),
-        )
-        .map(request => ({
-          ...request,
-          // `devicesPlatformDetails` is defined because otherwise, this device
-          // is going to be included in dead devices and filtered out, see
-          // `getPeersDeadDeviceIDs`.
-          platformDetails:
-            auxUserInfos[userID]?.devicesPlatformDetails?.[request.deviceID],
-        }));
+      const filteredDevices = devices.filter(
+        request =>
+          !runningPromises.current[userID][request.deviceID] &&
+          !deadDevices.has(request.deviceID),
+      );
 
       const promise = (async () => {
         const authMetadata = await getAuthMetadata();
@@ -115,11 +105,10 @@
     },
     [
       deadDevices,
-      auxUserInfos,
       getAuthMetadata,
       identityClient,
-      sendMessageToDevice,
       olmDebugLog,
+      sendMessageToDevice,
       refetchDeviceList,
     ],
   );
diff --git a/lib/keyserver-conn/keyserver-auth.js b/lib/keyserver-conn/keyserver-auth.js
--- a/lib/keyserver-conn/keyserver-auth.js
+++ b/lib/keyserver-conn/keyserver-auth.js
@@ -103,18 +103,10 @@
                 keyserverKeys.identityKeysBlob.notificationIdentityPublicKeys,
                 keyserverKeys.notifInitializationInfo,
                 keyserverID,
-                // Assuming the keyserver is always running on the newest
-                // version, Olm compatibility is not required unlike for other
-                // clients that might not be updated yet.
-                false,
               ),
               olmAPI.contentOutboundSessionCreator(
                 keyserverKeys.identityKeysBlob.primaryIdentityPublicKeys,
                 keyserverKeys.contentInitializationInfo,
-                // Assuming the keyserver is always running on the newest
-                // version, Olm compatibility is not required unlike for other
-                // clients that might not be updated yet.
-                false,
               ),
               getAuthMetadata(),
             ]);
diff --git a/lib/shared/crypto-utils.js b/lib/shared/crypto-utils.js
--- a/lib/shared/crypto-utils.js
+++ b/lib/shared/crypto-utils.js
@@ -72,10 +72,6 @@
         notificationIdentityPublicKeys,
         notifInitializationInfo,
         keyserverID,
-        // Assuming the keyserver is always running on the newest
-        // version, Olm compatibility is not required unlike for other
-        // clients that might not be updated yet.
-        false,
       );
     },
     [
diff --git a/lib/types/crypto-types.js b/lib/types/crypto-types.js
--- a/lib/types/crypto-types.js
+++ b/lib/types/crypto-types.js
@@ -173,7 +173,6 @@
   +contentOutboundSessionCreator: (
     contentIdentityKeys: OLMIdentityKeys,
     contentInitializationInfo: OlmSessionInitializationInfo,
-    olmCompatibilityMode: boolean,
   ) => Promise<OutboundSessionCreationResult>,
   +isContentSessionInitialized: (deviceID: string) => Promise<boolean>,
   +keyserverNotificationsSessionCreator: (
@@ -181,13 +180,11 @@
     notificationsIdentityKeys: OLMIdentityKeys,
     notificationsInitializationInfo: OlmSessionInitializationInfo,
     keyserverID: string,
-    olmCompatibilityMode: boolean,
   ) => Promise<string>,
   +notificationsOutboundSessionCreator: (
     deviceID: string,
     notificationsIdentityKeys: OLMIdentityKeys,
     notificationsInitializationInfo: OlmSessionInitializationInfo,
-    olmCompatibilityMode: boolean,
   ) => Promise<EncryptedData>,
   +isDeviceNotificationsSessionInitialized: (
     deviceID: string,
diff --git a/lib/utils/crypto-utils.js b/lib/utils/crypto-utils.js
--- a/lib/utils/crypto-utils.js
+++ b/lib/utils/crypto-utils.js
@@ -5,7 +5,6 @@
 
 import { getConfig } from './config.js';
 import { getMessageForException } from './errors.js';
-import { olmSupportRequired } from './olm-support-required.js';
 import { primaryIdentityPublicKeyRegex } from './siwe-utils.js';
 import { tRegex, tShape } from './validation-utils.js';
 import type { OlmDebugLog } from '../components/debug-logs-context.js';
@@ -17,10 +16,7 @@
   OutboundSessionCreationResult,
   SignedIdentityKeysBlob,
 } from '../types/crypto-types.js';
-import type {
-  IdentityPlatformDetails,
-  IdentityServiceClient,
-} from '../types/identity-service-types';
+import type { IdentityServiceClient } from '../types/identity-service-types';
 import {
   type OutboundSessionCreation,
   peerToPeerMessageTypes,
@@ -81,13 +77,10 @@
     const recipientDeviceID = primaryIdentityPublicKeys.ed25519;
 
     try {
-      // This function is used for testing purposes only, available to staff
-      // users, so Olm support is hardcoded to false.
       const { sessionVersion, encryptedData } =
         await olmAPI.contentOutboundSessionCreator(
           primaryIdentityPublicKeys,
           keys.contentInitializationInfo,
-          false,
         );
 
       const sessionCreationMessage: OutboundSessionCreation = {
@@ -124,10 +117,6 @@
   +deviceID: string,
   +sessionCreationOptions?: SessionCreationOptions,
 };
-type DeviceSessionCreationRequestWithPlatformDetails = {
-  ...DeviceSessionCreationRequest,
-  platformDetails: ?IdentityPlatformDetails,
-};
 export type SessionCreationResult = {
   +deviceKeysMissing: boolean,
 };
@@ -136,7 +125,7 @@
   identityClient: IdentityServiceClient,
   sendMessage: (message: TunnelbrokerClientMessageToDevice) => Promise<void>,
   userID: string,
-  devices: $ReadOnlyArray<DeviceSessionCreationRequestWithPlatformDetails>,
+  devices: $ReadOnlyArray<DeviceSessionCreationRequest>,
   source: 'session_reset' | 'session_not_exists',
   olmDebugLog: (olmLog: OlmDebugLog) => mixed,
 ): Promise<SessionCreationResult> {
@@ -158,7 +147,6 @@
     +deviceID: string,
     +hasContentSession: boolean,
     +hasNotifsSession: boolean,
-    +olmSupport: boolean,
   }> = await Promise.all(
     devices.map(request =>
       (async () => {
@@ -182,7 +170,6 @@
           deviceID: request.deviceID,
           hasContentSession,
           hasNotifsSession,
-          olmSupport: olmSupportRequired(request.platformDetails),
         };
       })(),
     ),
@@ -206,8 +193,7 @@
       success = false,
       sessionVersionResult = -1;
     try {
-      const { deviceID, hasContentSession, hasNotifsSession, olmSupport } =
-        sessionRequest;
+      const { deviceID, hasContentSession, hasNotifsSession } = sessionRequest;
       const deviceKeysResponse = keysResponse.find(
         keys => keys.deviceID === deviceID,
       );
@@ -229,7 +215,6 @@
           recipientDeviceID,
           notificationIdentityPublicKeys,
           keys.notifInitializationInfo,
-          olmSupport,
         );
         success = true;
         return;
@@ -242,7 +227,6 @@
           await olmAPI.contentOutboundSessionCreator(
             primaryIdentityPublicKeys,
             keys.contentInitializationInfo,
-            olmSupport,
           );
       } else {
         resultDescription = 'creating content and notif session';
@@ -250,13 +234,11 @@
           await olmAPI.contentOutboundSessionCreator(
             primaryIdentityPublicKeys,
             keys.contentInitializationInfo,
-            olmSupport,
           ),
           olmAPI.notificationsOutboundSessionCreator(
             recipientDeviceID,
             notificationIdentityPublicKeys,
             keys.notifInitializationInfo,
-            olmSupport,
           ),
         ]);
       }
diff --git a/native/cpp/CommonCpp/CryptoTools/CryptoModule.h b/native/cpp/CommonCpp/CryptoTools/CryptoModule.h
--- a/native/cpp/CommonCpp/CryptoTools/CryptoModule.h
+++ b/native/cpp/CommonCpp/CryptoTools/CryptoModule.h
@@ -64,8 +64,7 @@
       const std::string &idKeys,
       const std::string &preKeys,
       const std::string &preKeySignature,
-      const std::optional<std::string> &oneTimeKey,
-      bool olmCompatibilityMode);
+      const std::optional<std::string> &oneTimeKey);
   bool hasSessionFor(const std::string &targetDeviceId);
   std::shared_ptr<Session> getSessionByDeviceId(const std::string &deviceId);
   void removeSessionByDeviceId(const std::string &deviceId);
diff --git a/native/cpp/CommonCpp/CryptoTools/CryptoModule.cpp b/native/cpp/CommonCpp/CryptoTools/CryptoModule.cpp
--- a/native/cpp/CommonCpp/CryptoTools/CryptoModule.cpp
+++ b/native/cpp/CommonCpp/CryptoTools/CryptoModule.cpp
@@ -238,8 +238,7 @@
     const std::string &idKeys,
     const std::string &preKeys,
     const std::string &preKeySignature,
-    const std::optional<std::string> &oneTimeKey,
-    bool olmCompatibilityMode) {
+    const std::optional<std::string> &oneTimeKey) {
   int newSessionVersion = 1;
   if (this->hasSessionFor(targetDeviceId)) {
     std::shared_ptr<Session> existingSession =
@@ -257,7 +256,7 @@
       preKeys,
       preKeySignature,
       oneTimeKey,
-      olmCompatibilityMode);
+      true); // olmCompatibilityMode = true
 
   newSession->setVersion(newSessionVersion);
   this->sessions.insert(make_pair(targetDeviceId, std::move(newSession)));
diff --git a/native/cpp/CommonCpp/NativeModules/CommCoreModule.h b/native/cpp/CommonCpp/NativeModules/CommCoreModule.h
--- a/native/cpp/CommonCpp/NativeModules/CommCoreModule.h
+++ b/native/cpp/CommonCpp/NativeModules/CommCoreModule.h
@@ -107,8 +107,7 @@
       jsi::String prekey,
       jsi::String prekeySignature,
       std::optional<jsi::String> oneTimeKey,
-      jsi::String keyserverID,
-      bool olmCompatibilityMode) override;
+      jsi::String keyserverID) override;
   virtual jsi::Value
   isNotificationsSessionInitialized(jsi::Runtime &rt) override;
   virtual jsi::Value isDeviceNotificationsSessionInitialized(
@@ -134,8 +133,7 @@
       jsi::String prekey,
       jsi::String prekeySignature,
       std::optional<jsi::String> oneTimeKey,
-      jsi::String deviceID,
-      bool olmCompatibilityMode) override;
+      jsi::String deviceID) override;
   virtual jsi::Value initializeContentInboundSession(
       jsi::Runtime &rt,
       jsi::String identityKeys,
@@ -151,8 +149,7 @@
       jsi::String prekey,
       jsi::String prekeySignature,
       std::optional<jsi::String> oneTimeKey,
-      jsi::String deviceID,
-      bool olmCompatibilityMode) override;
+      jsi::String deviceID) override;
   virtual jsi::Value
   encrypt(jsi::Runtime &rt, jsi::String message, jsi::String deviceID) override;
   virtual jsi::Value encryptNotification(
diff --git a/native/cpp/CommonCpp/NativeModules/CommCoreModule.cpp b/native/cpp/CommonCpp/NativeModules/CommCoreModule.cpp
--- a/native/cpp/CommonCpp/NativeModules/CommCoreModule.cpp
+++ b/native/cpp/CommonCpp/NativeModules/CommCoreModule.cpp
@@ -1152,8 +1152,7 @@
     jsi::String prekey,
     jsi::String prekeySignature,
     std::optional<jsi::String> oneTimeKey,
-    jsi::String keyserverID,
-    bool olmCompatibilityMode) {
+    jsi::String keyserverID) {
   auto identityKeysCpp{identityKeys.utf8(rt)};
   auto prekeyCpp{prekey.utf8(rt)};
   auto prekeySignatureCpp{prekeySignature.utf8(rt)};
@@ -1182,8 +1181,7 @@
                     identityKeysCpp,
                     prekeyCpp,
                     prekeySignatureCpp,
-                    oneTimeKeyCpp,
-                    olmCompatibilityMode);
+                    oneTimeKeyCpp);
 
             result = notifsCryptoModuleWithPicklingKey.value().first->encrypt(
                 keyserverIDCpp,
@@ -1528,8 +1526,7 @@
     jsi::String prekey,
     jsi::String prekeySignature,
     std::optional<jsi::String> oneTimeKey,
-    jsi::String deviceID,
-    bool olmCompatibilityMode) {
+    jsi::String deviceID) {
   auto identityKeysCpp{identityKeys.utf8(rt)};
   auto prekeyCpp{prekey.utf8(rt)};
   auto prekeySignatureCpp{prekeySignature.utf8(rt)};
@@ -1553,8 +1550,7 @@
                     identityKeysCpp,
                     prekeyCpp,
                     prekeySignatureCpp,
-                    oneTimeKeyCpp,
-                    olmCompatibilityMode);
+                    oneTimeKeyCpp);
 
             const std::string initMessage = "{\"type\": \"init\"}";
             initialEncryptedData =
@@ -1671,8 +1667,7 @@
     jsi::String prekey,
     jsi::String prekeySignature,
     std::optional<jsi::String> oneTimeKey,
-    jsi::String deviceID,
-    bool olmCompatibilityMode) {
+    jsi::String deviceID) {
   auto identityKeysCpp{identityKeys.utf8(rt)};
   auto prekeyCpp{prekey.utf8(rt)};
   auto prekeySignatureCpp{prekeySignature.utf8(rt)};
@@ -1700,8 +1695,7 @@
                     identityKeysCpp,
                     prekeyCpp,
                     prekeySignatureCpp,
-                    oneTimeKeyCpp,
-                    olmCompatibilityMode);
+                    oneTimeKeyCpp);
 
             result = notifsCryptoModuleWithPicklingKey.value().first->encrypt(
                 deviceIDCpp,
diff --git a/native/cpp/CommonCpp/_generated/commJSI-generated.cpp b/native/cpp/CommonCpp/_generated/commJSI-generated.cpp
--- a/native/cpp/CommonCpp/_generated/commJSI-generated.cpp
+++ b/native/cpp/CommonCpp/_generated/commJSI-generated.cpp
@@ -55,7 +55,7 @@
   return static_cast<CommCoreModuleSchemaCxxSpecJSI *>(&turboModule)->validateAndUploadPrekeys(rt, args[0].asString(rt), args[1].asString(rt), args[2].asString(rt));
 }
 static jsi::Value __hostFunction_CommCoreModuleSchemaCxxSpecJSI_initializeNotificationsSession(jsi::Runtime &rt, TurboModule &turboModule, const jsi::Value* args, size_t count) {
-  return static_cast<CommCoreModuleSchemaCxxSpecJSI *>(&turboModule)->initializeNotificationsSession(rt, args[0].asString(rt), args[1].asString(rt), args[2].asString(rt), args[3].isNull() || args[3].isUndefined() ? std::nullopt : std::make_optional(args[3].asString(rt)), args[4].asString(rt), args[5].asBool());
+  return static_cast<CommCoreModuleSchemaCxxSpecJSI *>(&turboModule)->initializeNotificationsSession(rt, args[0].asString(rt), args[1].asString(rt), args[2].asString(rt), args[3].isNull() || args[3].isUndefined() ? std::nullopt : std::make_optional(args[3].asString(rt)), args[4].asString(rt));
 }
 static jsi::Value __hostFunction_CommCoreModuleSchemaCxxSpecJSI_isNotificationsSessionInitialized(jsi::Runtime &rt, TurboModule &turboModule, const jsi::Value* args, size_t count) {
   return static_cast<CommCoreModuleSchemaCxxSpecJSI *>(&turboModule)->isNotificationsSessionInitialized(rt);
@@ -82,7 +82,7 @@
   return static_cast<CommCoreModuleSchemaCxxSpecJSI *>(&turboModule)->getUnreadThickThreadIDsFromNotifsStorage(rt);
 }
 static jsi::Value __hostFunction_CommCoreModuleSchemaCxxSpecJSI_initializeContentOutboundSession(jsi::Runtime &rt, TurboModule &turboModule, const jsi::Value* args, size_t count) {
-  return static_cast<CommCoreModuleSchemaCxxSpecJSI *>(&turboModule)->initializeContentOutboundSession(rt, args[0].asString(rt), args[1].asString(rt), args[2].asString(rt), args[3].isNull() || args[3].isUndefined() ? std::nullopt : std::make_optional(args[3].asString(rt)), args[4].asString(rt), args[5].asBool());
+  return static_cast<CommCoreModuleSchemaCxxSpecJSI *>(&turboModule)->initializeContentOutboundSession(rt, args[0].asString(rt), args[1].asString(rt), args[2].asString(rt), args[3].isNull() || args[3].isUndefined() ? std::nullopt : std::make_optional(args[3].asString(rt)), args[4].asString(rt));
 }
 static jsi::Value __hostFunction_CommCoreModuleSchemaCxxSpecJSI_initializeContentInboundSession(jsi::Runtime &rt, TurboModule &turboModule, const jsi::Value* args, size_t count) {
   return static_cast<CommCoreModuleSchemaCxxSpecJSI *>(&turboModule)->initializeContentInboundSession(rt, args[0].asString(rt), args[1].asObject(rt), args[2].asString(rt), args[3].asNumber(), args[4].asBool());
@@ -91,7 +91,7 @@
   return static_cast<CommCoreModuleSchemaCxxSpecJSI *>(&turboModule)->isContentSessionInitialized(rt, args[0].asString(rt));
 }
 static jsi::Value __hostFunction_CommCoreModuleSchemaCxxSpecJSI_initializeNotificationsOutboundSession(jsi::Runtime &rt, TurboModule &turboModule, const jsi::Value* args, size_t count) {
-  return static_cast<CommCoreModuleSchemaCxxSpecJSI *>(&turboModule)->initializeNotificationsOutboundSession(rt, args[0].asString(rt), args[1].asString(rt), args[2].asString(rt), args[3].isNull() || args[3].isUndefined() ? std::nullopt : std::make_optional(args[3].asString(rt)), args[4].asString(rt), args[5].asBool());
+  return static_cast<CommCoreModuleSchemaCxxSpecJSI *>(&turboModule)->initializeNotificationsOutboundSession(rt, args[0].asString(rt), args[1].asString(rt), args[2].asString(rt), args[3].isNull() || args[3].isUndefined() ? std::nullopt : std::make_optional(args[3].asString(rt)), args[4].asString(rt));
 }
 static jsi::Value __hostFunction_CommCoreModuleSchemaCxxSpecJSI_encrypt(jsi::Runtime &rt, TurboModule &turboModule, const jsi::Value* args, size_t count) {
   return static_cast<CommCoreModuleSchemaCxxSpecJSI *>(&turboModule)->encrypt(rt, args[0].asString(rt), args[1].asString(rt));
@@ -266,7 +266,7 @@
   methodMap_["getOneTimeKeys"] = MethodMetadata {1, __hostFunction_CommCoreModuleSchemaCxxSpecJSI_getOneTimeKeys};
   methodMap_["validateAndGetPrekeys"] = MethodMetadata {0, __hostFunction_CommCoreModuleSchemaCxxSpecJSI_validateAndGetPrekeys};
   methodMap_["validateAndUploadPrekeys"] = MethodMetadata {3, __hostFunction_CommCoreModuleSchemaCxxSpecJSI_validateAndUploadPrekeys};
-  methodMap_["initializeNotificationsSession"] = MethodMetadata {6, __hostFunction_CommCoreModuleSchemaCxxSpecJSI_initializeNotificationsSession};
+  methodMap_["initializeNotificationsSession"] = MethodMetadata {5, __hostFunction_CommCoreModuleSchemaCxxSpecJSI_initializeNotificationsSession};
   methodMap_["isNotificationsSessionInitialized"] = MethodMetadata {0, __hostFunction_CommCoreModuleSchemaCxxSpecJSI_isNotificationsSessionInitialized};
   methodMap_["isDeviceNotificationsSessionInitialized"] = MethodMetadata {1, __hostFunction_CommCoreModuleSchemaCxxSpecJSI_isDeviceNotificationsSessionInitialized};
   methodMap_["isNotificationsSessionInitializedWithDevices"] = MethodMetadata {1, __hostFunction_CommCoreModuleSchemaCxxSpecJSI_isNotificationsSessionInitializedWithDevices};
@@ -275,10 +275,10 @@
   methodMap_["getDataFromNotifStorage"] = MethodMetadata {1, __hostFunction_CommCoreModuleSchemaCxxSpecJSI_getDataFromNotifStorage};
   methodMap_["updateUnreadThickThreadsInNotifsStorage"] = MethodMetadata {1, __hostFunction_CommCoreModuleSchemaCxxSpecJSI_updateUnreadThickThreadsInNotifsStorage};
   methodMap_["getUnreadThickThreadIDsFromNotifsStorage"] = MethodMetadata {0, __hostFunction_CommCoreModuleSchemaCxxSpecJSI_getUnreadThickThreadIDsFromNotifsStorage};
-  methodMap_["initializeContentOutboundSession"] = MethodMetadata {6, __hostFunction_CommCoreModuleSchemaCxxSpecJSI_initializeContentOutboundSession};
+  methodMap_["initializeContentOutboundSession"] = MethodMetadata {5, __hostFunction_CommCoreModuleSchemaCxxSpecJSI_initializeContentOutboundSession};
   methodMap_["initializeContentInboundSession"] = MethodMetadata {5, __hostFunction_CommCoreModuleSchemaCxxSpecJSI_initializeContentInboundSession};
   methodMap_["isContentSessionInitialized"] = MethodMetadata {1, __hostFunction_CommCoreModuleSchemaCxxSpecJSI_isContentSessionInitialized};
-  methodMap_["initializeNotificationsOutboundSession"] = MethodMetadata {6, __hostFunction_CommCoreModuleSchemaCxxSpecJSI_initializeNotificationsOutboundSession};
+  methodMap_["initializeNotificationsOutboundSession"] = MethodMetadata {5, __hostFunction_CommCoreModuleSchemaCxxSpecJSI_initializeNotificationsOutboundSession};
   methodMap_["encrypt"] = MethodMetadata {2, __hostFunction_CommCoreModuleSchemaCxxSpecJSI_encrypt};
   methodMap_["encryptNotification"] = MethodMetadata {2, __hostFunction_CommCoreModuleSchemaCxxSpecJSI_encryptNotification};
   methodMap_["encryptAndPersist"] = MethodMetadata {3, __hostFunction_CommCoreModuleSchemaCxxSpecJSI_encryptAndPersist};
diff --git a/native/cpp/CommonCpp/_generated/commJSI.h b/native/cpp/CommonCpp/_generated/commJSI.h
--- a/native/cpp/CommonCpp/_generated/commJSI.h
+++ b/native/cpp/CommonCpp/_generated/commJSI.h
@@ -33,7 +33,7 @@
   virtual jsi::Value getOneTimeKeys(jsi::Runtime &rt, double oneTimeKeysAmount) = 0;
   virtual jsi::Value validateAndGetPrekeys(jsi::Runtime &rt) = 0;
   virtual jsi::Value validateAndUploadPrekeys(jsi::Runtime &rt, jsi::String authUserID, jsi::String authDeviceID, jsi::String authAccessToken) = 0;
-  virtual jsi::Value initializeNotificationsSession(jsi::Runtime &rt, jsi::String identityKeys, jsi::String prekey, jsi::String prekeySignature, std::optional<jsi::String> oneTimeKey, jsi::String keyserverID, bool olmCompatibilityMode) = 0;
+  virtual jsi::Value initializeNotificationsSession(jsi::Runtime &rt, jsi::String identityKeys, jsi::String prekey, jsi::String prekeySignature, std::optional<jsi::String> oneTimeKey, jsi::String keyserverID) = 0;
   virtual jsi::Value isNotificationsSessionInitialized(jsi::Runtime &rt) = 0;
   virtual jsi::Value isDeviceNotificationsSessionInitialized(jsi::Runtime &rt, jsi::String deviceID) = 0;
   virtual jsi::Value isNotificationsSessionInitializedWithDevices(jsi::Runtime &rt, jsi::Array deviceIDs) = 0;
@@ -42,10 +42,10 @@
   virtual jsi::Value getDataFromNotifStorage(jsi::Runtime &rt, jsi::Array ids) = 0;
   virtual jsi::Value updateUnreadThickThreadsInNotifsStorage(jsi::Runtime &rt, jsi::Array unreadThickThreadIDs) = 0;
   virtual jsi::Value getUnreadThickThreadIDsFromNotifsStorage(jsi::Runtime &rt) = 0;
-  virtual jsi::Value initializeContentOutboundSession(jsi::Runtime &rt, jsi::String identityKeys, jsi::String prekey, jsi::String prekeySignature, std::optional<jsi::String> oneTimeKey, jsi::String deviceID, bool olmCompatibilityMode) = 0;
+  virtual jsi::Value initializeContentOutboundSession(jsi::Runtime &rt, jsi::String identityKeys, jsi::String prekey, jsi::String prekeySignature, std::optional<jsi::String> oneTimeKey, jsi::String deviceID) = 0;
   virtual jsi::Value initializeContentInboundSession(jsi::Runtime &rt, jsi::String identityKeys, jsi::Object encryptedContent, jsi::String deviceID, double sessionVersion, bool overwrite) = 0;
   virtual jsi::Value isContentSessionInitialized(jsi::Runtime &rt, jsi::String deviceID) = 0;
-  virtual jsi::Value initializeNotificationsOutboundSession(jsi::Runtime &rt, jsi::String identityKeys, jsi::String prekey, jsi::String prekeySignature, std::optional<jsi::String> oneTimeKey, jsi::String deviceID, bool olmCompatibilityMode) = 0;
+  virtual jsi::Value initializeNotificationsOutboundSession(jsi::Runtime &rt, jsi::String identityKeys, jsi::String prekey, jsi::String prekeySignature, std::optional<jsi::String> oneTimeKey, jsi::String deviceID) = 0;
   virtual jsi::Value encrypt(jsi::Runtime &rt, jsi::String message, jsi::String deviceID) = 0;
   virtual jsi::Value encryptNotification(jsi::Runtime &rt, jsi::String payload, jsi::String deviceID) = 0;
   virtual jsi::Value encryptAndPersist(jsi::Runtime &rt, jsi::String message, jsi::String deviceID, jsi::String messageID) = 0;
@@ -222,13 +222,13 @@
       return bridging::callFromJs<jsi::Value>(
           rt, &T::validateAndUploadPrekeys, jsInvoker_, instance_, std::move(authUserID), std::move(authDeviceID), std::move(authAccessToken));
     }
-    jsi::Value initializeNotificationsSession(jsi::Runtime &rt, jsi::String identityKeys, jsi::String prekey, jsi::String prekeySignature, std::optional<jsi::String> oneTimeKey, jsi::String keyserverID, bool olmCompatibilityMode) override {
+    jsi::Value initializeNotificationsSession(jsi::Runtime &rt, jsi::String identityKeys, jsi::String prekey, jsi::String prekeySignature, std::optional<jsi::String> oneTimeKey, jsi::String keyserverID) override {
       static_assert(
-          bridging::getParameterCount(&T::initializeNotificationsSession) == 7,
-          "Expected initializeNotificationsSession(...) to have 7 parameters");
+          bridging::getParameterCount(&T::initializeNotificationsSession) == 6,
+          "Expected initializeNotificationsSession(...) to have 6 parameters");
 
       return bridging::callFromJs<jsi::Value>(
-          rt, &T::initializeNotificationsSession, jsInvoker_, instance_, std::move(identityKeys), std::move(prekey), std::move(prekeySignature), std::move(oneTimeKey), std::move(keyserverID), std::move(olmCompatibilityMode));
+          rt, &T::initializeNotificationsSession, jsInvoker_, instance_, std::move(identityKeys), std::move(prekey), std::move(prekeySignature), std::move(oneTimeKey), std::move(keyserverID));
     }
     jsi::Value isNotificationsSessionInitialized(jsi::Runtime &rt) override {
       static_assert(
@@ -294,13 +294,13 @@
       return bridging::callFromJs<jsi::Value>(
           rt, &T::getUnreadThickThreadIDsFromNotifsStorage, jsInvoker_, instance_);
     }
-    jsi::Value initializeContentOutboundSession(jsi::Runtime &rt, jsi::String identityKeys, jsi::String prekey, jsi::String prekeySignature, std::optional<jsi::String> oneTimeKey, jsi::String deviceID, bool olmCompatibilityMode) override {
+    jsi::Value initializeContentOutboundSession(jsi::Runtime &rt, jsi::String identityKeys, jsi::String prekey, jsi::String prekeySignature, std::optional<jsi::String> oneTimeKey, jsi::String deviceID) override {
       static_assert(
-          bridging::getParameterCount(&T::initializeContentOutboundSession) == 7,
-          "Expected initializeContentOutboundSession(...) to have 7 parameters");
+          bridging::getParameterCount(&T::initializeContentOutboundSession) == 6,
+          "Expected initializeContentOutboundSession(...) to have 6 parameters");
 
       return bridging::callFromJs<jsi::Value>(
-          rt, &T::initializeContentOutboundSession, jsInvoker_, instance_, std::move(identityKeys), std::move(prekey), std::move(prekeySignature), std::move(oneTimeKey), std::move(deviceID), std::move(olmCompatibilityMode));
+          rt, &T::initializeContentOutboundSession, jsInvoker_, instance_, std::move(identityKeys), std::move(prekey), std::move(prekeySignature), std::move(oneTimeKey), std::move(deviceID));
     }
     jsi::Value initializeContentInboundSession(jsi::Runtime &rt, jsi::String identityKeys, jsi::Object encryptedContent, jsi::String deviceID, double sessionVersion, bool overwrite) override {
       static_assert(
@@ -318,13 +318,13 @@
       return bridging::callFromJs<jsi::Value>(
           rt, &T::isContentSessionInitialized, jsInvoker_, instance_, std::move(deviceID));
     }
-    jsi::Value initializeNotificationsOutboundSession(jsi::Runtime &rt, jsi::String identityKeys, jsi::String prekey, jsi::String prekeySignature, std::optional<jsi::String> oneTimeKey, jsi::String deviceID, bool olmCompatibilityMode) override {
+    jsi::Value initializeNotificationsOutboundSession(jsi::Runtime &rt, jsi::String identityKeys, jsi::String prekey, jsi::String prekeySignature, std::optional<jsi::String> oneTimeKey, jsi::String deviceID) override {
       static_assert(
-          bridging::getParameterCount(&T::initializeNotificationsOutboundSession) == 7,
-          "Expected initializeNotificationsOutboundSession(...) to have 7 parameters");
+          bridging::getParameterCount(&T::initializeNotificationsOutboundSession) == 6,
+          "Expected initializeNotificationsOutboundSession(...) to have 6 parameters");
 
       return bridging::callFromJs<jsi::Value>(
-          rt, &T::initializeNotificationsOutboundSession, jsInvoker_, instance_, std::move(identityKeys), std::move(prekey), std::move(prekeySignature), std::move(oneTimeKey), std::move(deviceID), std::move(olmCompatibilityMode));
+          rt, &T::initializeNotificationsOutboundSession, jsInvoker_, instance_, std::move(identityKeys), std::move(prekey), std::move(prekeySignature), std::move(oneTimeKey), std::move(deviceID));
     }
     jsi::Value encrypt(jsi::Runtime &rt, jsi::String message, jsi::String deviceID) override {
       static_assert(
diff --git a/native/crypto/olm-api.js b/native/crypto/olm-api.js
--- a/native/crypto/olm-api.js
+++ b/native/crypto/olm-api.js
@@ -58,7 +58,6 @@
   async contentOutboundSessionCreator(
     contentIdentityKeys: OLMIdentityKeys,
     contentInitializationInfo: OlmSessionInitializationInfo,
-    olmCompatibilityMode: boolean,
   ): Promise<OutboundSessionCreationResult> {
     const { prekey, prekeySignature, oneTimeKey } = contentInitializationInfo;
     const identityKeys = JSON.stringify({
@@ -72,7 +71,6 @@
       prekeySignature,
       oneTimeKey,
       contentIdentityKeys.ed25519,
-      olmCompatibilityMode,
     );
   },
   keyserverNotificationsSessionCreator(
@@ -80,7 +78,6 @@
     notificationsIdentityKeys: OLMIdentityKeys,
     notificationsInitializationInfo: OlmSessionInitializationInfo,
     keyserverID: string,
-    olmCompatibilityMode: boolean,
   ): Promise<string> {
     const { prekey, prekeySignature, oneTimeKey } =
       notificationsInitializationInfo;
@@ -90,14 +87,12 @@
       prekeySignature,
       oneTimeKey,
       keyserverID,
-      olmCompatibilityMode,
     );
   },
   async notificationsOutboundSessionCreator(
     deviceID: string,
     notificationsIdentityKeys: OLMIdentityKeys,
     notificationsInitializationInfo: OlmSessionInitializationInfo,
-    olmCompatibilityMode: boolean,
   ): Promise<EncryptedData> {
     const { prekey, prekeySignature, oneTimeKey } =
       notificationsInitializationInfo;
@@ -111,7 +106,6 @@
       prekeySignature,
       oneTimeKey,
       deviceID,
-      olmCompatibilityMode,
     );
   },
   isDeviceNotificationsSessionInitialized:
diff --git a/native/schema/CommCoreModuleSchema.js b/native/schema/CommCoreModuleSchema.js
--- a/native/schema/CommCoreModuleSchema.js
+++ b/native/schema/CommCoreModuleSchema.js
@@ -73,7 +73,6 @@
     prekeySignature: string,
     oneTimeKey: ?string,
     keyserverID: string,
-    olmCompatibilityMode: boolean,
   ) => Promise<string>;
   +isNotificationsSessionInitialized: () => Promise<boolean>;
   +isDeviceNotificationsSessionInitialized: (
@@ -103,7 +102,6 @@
     prekeySignature: string,
     oneTimeKey: ?string,
     deviceID: string,
-    olmCompatibilityMode: boolean,
   ) => Promise<OutboundSessionCreationResult>;
   +initializeContentInboundSession: (
     identityKeys: string,
@@ -119,7 +117,6 @@
     prekeySignature: string,
     oneTimeKey: ?string,
     deviceID: string,
-    olmCompatibilityMode: boolean,
   ) => Promise<EncryptedData>;
   +encrypt: (message: string, deviceID: string) => Promise<EncryptedData>;
   +encryptNotification: (
diff --git a/web/shared-worker/worker/worker-crypto.js b/web/shared-worker/worker/worker-crypto.js
--- a/web/shared-worker/worker/worker-crypto.js
+++ b/web/shared-worker/worker/worker-crypto.js
@@ -185,7 +185,6 @@
   notificationsInitializationInfo: OlmSessionInitializationInfo,
   dataPersistenceKey: string,
   dataEncryptionKeyDBLabel: string,
-  olmCompatibilityMode: boolean,
 ): Promise<EncryptedData> {
   if (!cryptoStore) {
     throw new Error('Crypto account not initialized');
@@ -209,7 +208,7 @@
     notificationsInitializationInfo.oneTimeKey || '',
     notificationsPrekey,
     notificationsInitializationInfo.prekeySignature,
-    olmCompatibilityMode,
+    true, // olmCompatibilityMode
   );
 
   const encryptedMessage = session.encrypt(
@@ -842,7 +841,6 @@
   async contentOutboundSessionCreator(
     contentIdentityKeys: OLMIdentityKeys,
     contentInitializationInfo: OlmSessionInitializationInfo,
-    olmCompatibilityMode: boolean,
   ): Promise<OutboundSessionCreationResult> {
     if (!cryptoStore) {
       throw new Error('Crypto account not initialized');
@@ -858,7 +856,7 @@
       contentInitializationInfo.oneTimeKey || '',
       contentInitializationInfo.prekey,
       contentInitializationInfo.prekeySignature,
-      olmCompatibilityMode,
+      true, // olmCompatibilityMode
     );
 
     const olmMessage = session.encrypt(
@@ -898,7 +896,6 @@
     deviceID: string,
     notificationsIdentityKeys: OLMIdentityKeys,
     notificationsInitializationInfo: OlmSessionInitializationInfo,
-    olmCompatibilityMode: boolean,
   ): Promise<EncryptedData> {
     const dataPersistenceKey = getOlmDataKeyForDeviceID(deviceID);
     const dataEncryptionKeyDBLabel =
@@ -909,7 +906,6 @@
       notificationsInitializationInfo,
       dataPersistenceKey,
       dataEncryptionKeyDBLabel,
-      olmCompatibilityMode,
     );
   },
   async isDeviceNotificationsSessionInitialized(deviceID: string) {
@@ -948,7 +944,6 @@
     notificationsIdentityKeys: OLMIdentityKeys,
     notificationsInitializationInfo: OlmSessionInitializationInfo,
     keyserverID: string,
-    olmCompatibilityMode: boolean,
   ): Promise<string> {
     const platformDetails = getPlatformDetails();
     if (!platformDetails) {
@@ -963,7 +958,6 @@
       notificationsInitializationInfo,
       notifsOlmDataContentKey,
       notifsOlmDataEncryptionKeyDBLabel,
-      olmCompatibilityMode,
     );
 
     return message;