Tencent/MMKV v2.4.0 on GitHub

v2.4.0 / 2026-03-18 (Breaking Change)

This release introduces a unified MMKVHandler callback interface across all platforms, replacing scattered per-callback registration with a single, OO-style handler. It also adds the MMKVConfig all-in-one configuration and several bug fixes.

Changes for All Platforms

Feature: Refactored the callback system into a unified MMKVHandler interface. All callbacks (log redirecting, error handling, content change notification, content loaded notification) are now grouped in a single handler registered via registerHandler(). The old per-callback registerLogHandler() / registerErrorHandler() / registerContentChangeHandler() / registerContentLoadedHandler() APIs have been removed.
Feature: Added onMMKVContentLoadSuccessfully callback, triggered when an MMKV file is loaded/mapped successfully.
Feature: Added MMKVConfig for all-in-one instance configuration, supporting all options (mode, cryptKey, aes256, expectedCapacity, enableKeyExpire, expiredInSeconds, enableCompareBeforeSet, recover, itemSizeLimit) in a single struct/class.
Feature: Added defaultMMKV(config) variant for creating the default instance with full configuration.
Fix: Robust check on encryption mode (#1642).
Fix: Protect from delete file failure on corrupted files.
Fix: Protect from m_file not valid for isDiskOfMMAPFileCorrupted().
Fix: Reduce absolutePath() calls as much as possible.
Drop old-style actual size downgrade support.
MMKV must be compiled with C++17.

Android

Change: Merged MMKVContentChangeNotification into MMKVHandler. The old MMKVContentChangeNotification interface is now @Deprecated.
Fix: Fix fcntl() OFD lock failure on ashmem (#1637).
Merge ashmem size with expectedCapacity.
Correctly collect so-symbols.

iOS/macOS

Feature: Added getBytes() with string_view key for ObjC++.
Fix: Fixed a memory leak on getting NameSpace instance.
Support Swift Package Manager (#535).
Fix compile error on tryAtomicRename().

HarmonyOS NEXT

Merge ashmem size with expectedCapacity.

Flutter

Updated to use the unified MMKVHandler callback interface.

Win32

Fix: Convert log message to UTF-8 for Win32 client.
Verify all pages for corrupted file detection.