diff --git a/lib/actions/user-actions.js b/lib/actions/user-actions.js
--- a/lib/actions/user-actions.js
+++ b/lib/actions/user-actions.js
@@ -10,6 +10,7 @@
 } from '../keyserver-conn/keyserver-call-utils.js';
 import type { CallKeyserverEndpoint } from '../keyserver-conn/keyserver-conn-types.js';
 import { preRequestUserStateSelector } from '../selectors/account-selectors.js';
+import { getOneTimeKeyValuesFromBlob } from '../shared/crypto-utils.js';
 import { IdentityClientContext } from '../shared/identity-client-context.js';
 import threadWatcher from '../shared/thread-watcher.js';
 import type {
@@ -757,11 +758,26 @@
     options?: ?CallSingleKeyserverEndpointOptions,
   ) => Promise<GetOlmSessionInitializationDataResponse>) =>
   async options => {
-    return await callSingleKeyserverEndpoint(
+    const olmInitData = await callSingleKeyserverEndpoint(
       'get_olm_session_initialization_data',
       {},
       options,
     );
+    return {
+      signedIdentityKeysBlob: olmInitData.signedIdentityKeysBlob,
+      contentInitializationInfo: {
+        ...olmInitData.contentInitializationInfo,
+        oneTimeKey: getOneTimeKeyValuesFromBlob(
+          olmInitData.contentInitializationInfo.oneTimeKey,
+        )[0],
+      },
+      notifInitializationInfo: {
+        ...olmInitData.notifInitializationInfo,
+        oneTimeKey: getOneTimeKeyValuesFromBlob(
+          olmInitData.notifInitializationInfo.oneTimeKey,
+        )[0],
+      },
+    };
   };
 
 const policyAcknowledgmentActionTypes = Object.freeze({
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
@@ -17,7 +17,7 @@
   CallSingleKeyserverEndpointOptions,
   CallSingleKeyserverEndpoint,
 } from '../utils/call-single-keyserver-endpoint.js';
-import { values, entries } from '../utils/objects.js';
+import { values } from '../utils/objects.js';
 import { useDispatchActionPromise } from '../utils/redux-promise-utils.js';
 
 export type InitialNotifMessageOptions = {
@@ -104,14 +104,6 @@
   return getPrekeyValue(prekey);
 }
 
-function getOneTimeKeyArray(
-  oneTimeKeys: OLMOneTimeKeys,
-): $ReadOnlyArray<string> {
-  return entries(oneTimeKeys.curve25519).map(([key, value]: [string, string]) =>
-    JSON.stringify({ curve25519: { [key]: value } }),
-  );
-}
-
 export {
   getOneTimeKeyValues,
   getPrekeyValue,
@@ -119,5 +111,4 @@
   getPrekeyValueFromBlob,
   initialEncryptedMessageContent,
   useInitialNotificationsEncryptedMessage,
-  getOneTimeKeyArray,
 };
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 OlmBuffer &idKeys,
       const OlmBuffer &preKeys,
       const OlmBuffer &preKeySignature,
-      const OlmBuffer &oneTimeKeys,
-      size_t keyIndex = 0);
+      const OlmBuffer &oneTimeKey);
   bool hasSessionFor(const std::string &targetDeviceId);
   std::shared_ptr<Session> getSessionByDeviceId(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
@@ -284,8 +284,7 @@
     const OlmBuffer &idKeys,
     const OlmBuffer &preKeys,
     const OlmBuffer &preKeySignature,
-    const OlmBuffer &oneTimeKeys,
-    size_t keyIndex) {
+    const OlmBuffer &oneTimeKey) {
   if (this->hasSessionFor(targetDeviceId)) {
     Logger::log(
         "olm session overwritten for the device with id: " + targetDeviceId);
@@ -297,8 +296,7 @@
       idKeys,
       preKeys,
       preKeySignature,
-      oneTimeKeys,
-      keyIndex);
+      oneTimeKey);
   this->sessions.insert(make_pair(targetDeviceId, std::move(newSession)));
 }
 
diff --git a/native/cpp/CommonCpp/CryptoTools/Session.h b/native/cpp/CommonCpp/CryptoTools/Session.h
--- a/native/cpp/CommonCpp/CryptoTools/Session.h
+++ b/native/cpp/CommonCpp/CryptoTools/Session.h
@@ -27,8 +27,7 @@
       const OlmBuffer &idKeys,
       const OlmBuffer &preKeys,
       const OlmBuffer &preKeySignature,
-      const OlmBuffer &oneTimeKeys,
-      size_t keyIndex = 0);
+      const OlmBuffer &oneTimeKey);
   static std::unique_ptr<Session> createSessionAsResponder(
       OlmAccount *account,
       std::uint8_t *ownerIdentityKeys,
diff --git a/native/cpp/CommonCpp/CryptoTools/Session.cpp b/native/cpp/CommonCpp/CryptoTools/Session.cpp
--- a/native/cpp/CommonCpp/CryptoTools/Session.cpp
+++ b/native/cpp/CommonCpp/CryptoTools/Session.cpp
@@ -16,8 +16,7 @@
     const OlmBuffer &idKeys,
     const OlmBuffer &preKeys,
     const OlmBuffer &preKeySignature,
-    const OlmBuffer &oneTimeKeys,
-    size_t keyIndex) {
+    const OlmBuffer &oneTimeKey) {
   std::unique_ptr<Session> session(new Session(account, ownerIdentityKeys));
 
   session->olmSessionBuffer.resize(::olm_session_size());
@@ -40,8 +39,7 @@
           KEYSIZE,
           preKeySignature.data(),
           SIGNATURESIZE,
-          oneTimeKeys.data() + ONE_TIME_KEYS_PREFIX_OFFSET +
-              (KEYSIZE + ONE_TIME_KEYS_MIDDLE_OFFSET) * keyIndex,
+          oneTimeKey.data(),
           KEYSIZE,
           randomBuffer.data(),
           randomBuffer.size())) {
@@ -75,7 +73,7 @@
 
   if (-1 == ::olm_remove_one_time_keys(account, session->getOlmSession())) {
     throw std::runtime_error(
-        "error createInbound (remove oneTimeKeys) => " +
+        "error createInbound (remove oneTimeKey) => " +
         std::string{::olm_session_last_error(session->getOlmSession())});
   }
   return session;
diff --git a/native/cpp/CommonCpp/CryptoTools/Tools.h b/native/cpp/CommonCpp/CryptoTools/Tools.h
--- a/native/cpp/CommonCpp/CryptoTools/Tools.h
+++ b/native/cpp/CommonCpp/CryptoTools/Tools.h
@@ -11,8 +11,6 @@
 #define ID_KEYS_PREFIX_OFFSET 15
 #define SIGNING_KEYS_PREFIX_OFFSET 71
 #define PRE_KEY_PREFIX_OFFSET 25
-#define ONE_TIME_KEYS_PREFIX_OFFSET 25
-#define ONE_TIME_KEYS_MIDDLE_OFFSET 12
 
 #define ENCRYPTED_MESSAGE_TYPE 1
 
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
@@ -796,12 +796,12 @@
     jsi::String identityKeys,
     jsi::String prekey,
     jsi::String prekeySignature,
-    jsi::String oneTimeKeys,
+    jsi::String oneTimeKey,
     jsi::String keyserverID) {
   auto identityKeysCpp{identityKeys.utf8(rt)};
   auto prekeyCpp{prekey.utf8(rt)};
   auto prekeySignatureCpp{prekeySignature.utf8(rt)};
-  auto oneTimeKeysCpp{oneTimeKeys.utf8(rt)};
+  auto oneTimeKeyCpp{oneTimeKey.utf8(rt)};
   return createPromiseAsJSIValue(
       rt, [=](jsi::Runtime &innerRt, std::shared_ptr<Promise> promise) {
         taskType job = [=, &innerRt]() {
@@ -812,7 +812,7 @@
                 identityKeysCpp,
                 prekeyCpp,
                 prekeySignatureCpp,
-                oneTimeKeysCpp,
+                oneTimeKeyCpp,
                 "Comm");
           } catch (const std::exception &e) {
             error = e.what();
@@ -861,12 +861,12 @@
     jsi::String identityKeys,
     jsi::String prekey,
     jsi::String prekeySignature,
-    jsi::String oneTimeKeys,
+    jsi::String oneTimeKey,
     jsi::String deviceID) {
   auto identityKeysCpp{identityKeys.utf8(rt)};
   auto prekeyCpp{prekey.utf8(rt)};
   auto prekeySignatureCpp{prekeySignature.utf8(rt)};
-  auto oneTimeKeysCpp{oneTimeKeys.utf8(rt)};
+  auto oneTimeKeyCpp{oneTimeKey.utf8(rt)};
   auto deviceIDCpp{deviceID.utf8(rt)};
   return createPromiseAsJSIValue(
       rt, [=](jsi::Runtime &innerRt, std::shared_ptr<Promise> promise) {
@@ -882,7 +882,7 @@
                 std::vector<uint8_t>(
                     prekeySignatureCpp.begin(), prekeySignatureCpp.end()),
                 std::vector<uint8_t>(
-                    oneTimeKeysCpp.begin(), oneTimeKeysCpp.end()));
+                    oneTimeKeyCpp.begin(), oneTimeKeyCpp.end()));
 
             const std::string initMessage = "{\"type\": \"init\"}";
             initialEncryptedMessage =
diff --git a/native/cpp/CommonCpp/Notifications/BackgroundDataStorage/NotificationsCryptoModule.cpp b/native/cpp/CommonCpp/Notifications/BackgroundDataStorage/NotificationsCryptoModule.cpp
--- a/native/cpp/CommonCpp/Notifications/BackgroundDataStorage/NotificationsCryptoModule.cpp
+++ b/native/cpp/CommonCpp/Notifications/BackgroundDataStorage/NotificationsCryptoModule.cpp
@@ -241,7 +241,7 @@
     const std::string &identityKeys,
     const std::string &prekey,
     const std::string &prekeySignature,
-    const std::string &oneTimeKeys,
+    const std::string &oneTimeKey,
     const std::string &callingProcessName) {
   crypto::EncryptedData initialEncryptedMessage;
   auto caller = [&](const std::unique_ptr<crypto::CryptoModule> &cryptoModule) {
@@ -250,7 +250,7 @@
         std::vector<uint8_t>(identityKeys.begin(), identityKeys.end()),
         std::vector<uint8_t>(prekey.begin(), prekey.end()),
         std::vector<uint8_t>(prekeySignature.begin(), prekeySignature.end()),
-        std::vector<uint8_t>(oneTimeKeys.begin(), oneTimeKeys.end()));
+        std::vector<uint8_t>(oneTimeKey.begin(), oneTimeKey.end()));
     initialEncryptedMessage = cryptoModule->encrypt(
         NotificationsCryptoModule::keyserverHostedNotificationsID,
         NotificationsCryptoModule::initialEncryptedMessageContent);
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
@@ -41,9 +41,9 @@
   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, jsi::String oneTimeKeys, jsi::String keyserverID) = 0;
+  virtual jsi::Value initializeNotificationsSession(jsi::Runtime &rt, jsi::String identityKeys, jsi::String prekey, jsi::String prekeySignature, jsi::String oneTimeKey, jsi::String keyserverID) = 0;
   virtual jsi::Value isNotificationsSessionInitialized(jsi::Runtime &rt) = 0;
-  virtual jsi::Value initializeContentOutboundSession(jsi::Runtime &rt, jsi::String identityKeys, jsi::String prekey, jsi::String prekeySignature, jsi::String oneTimeKeys, jsi::String deviceID) = 0;
+  virtual jsi::Value initializeContentOutboundSession(jsi::Runtime &rt, jsi::String identityKeys, jsi::String prekey, jsi::String prekeySignature, jsi::String oneTimeKey, jsi::String deviceID) = 0;
   virtual jsi::Value initializeContentInboundSession(jsi::Runtime &rt, jsi::String identityKeys, jsi::String encryptedMessage, jsi::String deviceID) = 0;
   virtual jsi::Value encrypt(jsi::Runtime &rt, jsi::String message, jsi::String deviceID) = 0;
   virtual jsi::Value decrypt(jsi::Runtime &rt, jsi::String message, jsi::String deviceID) = 0;
@@ -255,13 +255,13 @@
       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, jsi::String oneTimeKeys, jsi::String keyserverID) override {
+    jsi::Value initializeNotificationsSession(jsi::Runtime &rt, jsi::String identityKeys, jsi::String prekey, jsi::String prekeySignature, jsi::String oneTimeKey, jsi::String keyserverID) override {
       static_assert(
           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(oneTimeKeys), std::move(keyserverID));
+          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(
@@ -271,13 +271,13 @@
       return bridging::callFromJs<jsi::Value>(
           rt, &T::isNotificationsSessionInitialized, jsInvoker_, instance_);
     }
-    jsi::Value initializeContentOutboundSession(jsi::Runtime &rt, jsi::String identityKeys, jsi::String prekey, jsi::String prekeySignature, jsi::String oneTimeKeys, jsi::String deviceID) override {
+    jsi::Value initializeContentOutboundSession(jsi::Runtime &rt, jsi::String identityKeys, jsi::String prekey, jsi::String prekeySignature, jsi::String oneTimeKey, jsi::String deviceID) override {
       static_assert(
           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(oneTimeKeys), std::move(deviceID));
+          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::String encryptedMessage, jsi::String deviceID) override {
       static_assert(
diff --git a/native/handlers/peer-to-peer-message-handler.js b/native/handlers/peer-to-peer-message-handler.js
--- a/native/handlers/peer-to-peer-message-handler.js
+++ b/native/handlers/peer-to-peer-message-handler.js
@@ -1,6 +1,6 @@
 // @flow
 
-import { getOneTimeKeyArray } from 'lib/shared/crypto-utils.js';
+import { getOneTimeKeyValues } from 'lib/shared/crypto-utils.js';
 import {
   type PeerToPeerMessage,
   peerToPeerMessageTypes,
@@ -64,8 +64,8 @@
         userID,
         deviceID,
         accessToken,
-        getOneTimeKeyArray(contentOneTimeKeys),
-        getOneTimeKeyArray(notificationsOneTimeKeys),
+        getOneTimeKeyValues(contentOneTimeKeys),
+        getOneTimeKeyValues(notificationsOneTimeKeys),
       );
     } catch (e) {
       console.log(`Error uploading one-time keys: ${e.message}`);
diff --git a/native/schema/CommCoreModuleSchema.js b/native/schema/CommCoreModuleSchema.js
--- a/native/schema/CommCoreModuleSchema.js
+++ b/native/schema/CommCoreModuleSchema.js
@@ -95,7 +95,7 @@
     identityKeys: string,
     prekey: string,
     prekeySignature: string,
-    oneTimeKeys: string,
+    oneTimeKey: string,
     keyserverID: string,
   ) => Promise<string>;
   +isNotificationsSessionInitialized: () => Promise<boolean>;
@@ -103,7 +103,7 @@
     identityKeys: string,
     prekey: string,
     prekeySignature: string,
-    oneTimeKeys: string,
+    oneTimeKey: string,
     deviceID: string,
   ) => Promise<string>;
   +initializeContentInboundSession: (
diff --git a/web/account/account-hooks.js b/web/account/account-hooks.js
--- a/web/account/account-hooks.js
+++ b/web/account/account-hooks.js
@@ -8,7 +8,6 @@
 
 import {
   initialEncryptedMessageContent,
-  getOneTimeKeyValuesFromBlob,
   getPrekeyValueFromBlob,
 } from 'lib/shared/crypto-utils.js';
 import { OlmSessionCreatorContext } from 'lib/shared/olm-session-creator-context.js';
@@ -262,9 +261,6 @@
       const notificationsPrekey = getPrekeyValueFromBlob(
         notificationsInitializationInfo.prekey,
       );
-      const [notificationsOneTimeKey] = getOneTimeKeyValuesFromBlob(
-        notificationsInitializationInfo.oneTimeKey,
-      );
 
       const session = new olm.Session();
       session.create_outbound(
@@ -273,7 +269,7 @@
         notificationsIdentityKeys.ed25519,
         notificationsPrekey,
         notificationsInitializationInfo.prekeySignature,
-        notificationsOneTimeKey,
+        notificationsInitializationInfo.oneTimeKey,
       );
       const { body: initialNotificationsEncryptedMessage } = session.encrypt(
         JSON.stringify(initialEncryptedMessageContent),
@@ -341,9 +337,6 @@
       const contentPrekey = getPrekeyValueFromBlob(
         contentInitializationInfo.prekey,
       );
-      const [contentOneTimeKey] = getOneTimeKeyValuesFromBlob(
-        contentInitializationInfo.oneTimeKey,
-      );
 
       const session = new olm.Session();
       session.create_outbound(
@@ -352,7 +345,7 @@
         contentIdentityKeys.ed25519,
         contentPrekey,
         contentInitializationInfo.prekeySignature,
-        contentOneTimeKey,
+        contentInitializationInfo.oneTimeKey,
       );
       const { body: initialContentEncryptedMessage } = session.encrypt(
         JSON.stringify(initialEncryptedMessageContent),