MMKV Change Log

March 18, 2026 · View on GitHub

v2.4.0 / 2026-03-18

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.

v2.3.0 / 2025-12-03 (Breaking Change)

This release is a breaking change and introduces AES-256 encryption for enhanced security.

All Platforms

Feature: Added AES-256 encryption functionality. To upgrade an existing encrypted MMKV instance to AES-256, first load it using the old key. Then, call the reKey() method with the new key and set the aes256 parameter to true, e.g., reKey(newKey, aes256=true). After this, you should use the new key for all future loads of this instance.
Fix: Resolved a crash that occurred when loading an empty file in ReadOnly mode.
Fix: Added protection against the weakly_canonical() exception caused by an invalid file path.
Fix: Fixed an issue where the file size could change during multi-process loading.
Fix: Corrected a bug where a single key could be overridden incorrectly when upgrading from a v1.1.x version.

iOS/macOS/watchOS

Change: Dropped support for the armv7k architecture on Apple Watch. To adapt, you should add armv7k to the "Excluded Architectures" setting for your Apple Watch App or Extension target.
Important: Do not upgrade to this version if you need to maintain armv7k support.
Change: Dropped deprecated methods that use the relativePath: parameter. If you were using these methods, please migrate to those using the rootPath: parameter instead.

POSIX

Change: Dropped support for armv7 architecture. Do not upgrade to this version if you need to maintain armv7 support.

v2.2.4 / 2025-09-25

This is a hotfix release mainly for iOS/macOS CocoaPods users.

Changes for All platforms

Improve the performance of MMBuffer a little bit in some cases.

iOS/macOS

Make MMKV and MMKVCore podspec define modules.

v2.2.3 / 2025-08-20

This is a feature release that brings full desktop support to Flutter. It also includes key bug fixes and enhancements for Android and other platforms.

Flutter

Added Full Desktop Support: MMKV for Flutter now officially supports Windows, macOS, and Linux.
Example App: The example application has been updated to run on all new desktop platforms.

Android

Feature: Added MMKVHandler.getNativeLogHandler() to allow native handling of MMKV logs from C++ code, improving performance.
Fix: Corrected an integer overflow bug where a native memory address exceeding Long.MAX_VALUE was misinterpreted as a negative number.
Fix: Prevented potential memory overflow by ensuring JNI local references are deleted after use.
Fix: Fixed an issue where directories for special relative paths were not being created correctly.
Enhancement: Improved the thread-safety of the callback handler to prevent crashes.

iOS/macOS

Fix: Resolved a build error on Apple platforms that occurred when the MMKV_APPLE flag was not set.
Fix: Addressed a naming conflict in the Swift implementation.

Windows

Fix: Corrected character encoding issues in the Win32 demo by converting files to UTF-8.

v2.2.2 / 2025-05-08

This is a hot fix version mainly for Android/Linux platforms. It’s highly recommended for v2.2.0~v2.2.1 users.

Changes for All platforms

Improve file lock consistency for Mayfly FD MMKV instances.

Android

Fix a potential ANR on multi-process mode MMKV init/creation.

POSIX

Fix a potential ANR on multi-process mode MMKV init/creation on Linux.

iOS/macOS

Retain the callback handler to prevent a potential short-lived callback handler from crashing.

Win32

Improve efficiency on MMKV instance init/creation.

v2.2.1 / 2025-04-25

Changes for All platforms

Add importFrom().

Android

Fix a bug on initialization.

v2.2.0 / 2025-04-24

We introduce the Mayfly FD (short-lived file descriptor) enhancement, reducing MMKV's fd footprint by half and more. For a single-process mode MMKV instance, the fd footprint is reduced to zero (except Android/OHOS, details below). For a multi-process mode MMKV instance, the fd footprint is reduced by half, for we still need a long-lived fd to inter-process lock the shared memory.

Changes for All platforms

Add Mayfly FD (short-lived file descriptor) enhancement.
Improve multi-process access efficiency by about 20%.
Add checkExist() to check if a MMKV instance exists on disk.
Drop deprecated armv7 AES hardware acceleration.

Android

Reduce the fd footprint by half. For a single-process mode MMKV instance, we still need a long-lived fd to support the process-mode checker and legacy name upgrading. In the far future, when all legacy names have been upgraded, we might drop the long-lived fd like other platforms.
Upgrade Android compileSdk/targetSdk to 35, NDK to 28.1, Java to 11, Gradle to 8.11.1, and AGP to 8.9.2.

HarmonyOS NEXT

Reduce the fd footprint by half. For a single-process mode MMKV instance, we still need a long-lived fd to support the legacy name upgrading. In the far future, when all legacy names have been upgraded, we might drop the long-lived fd like other platforms.
Drop checkProcessMode(), it’s never been used.
Improve obfuscation configuration with relative path.

iOS

Add +mmkvGroupPath to get the group folder for MMKV multi-process storage.

Flutter

Add isFileValid().
Add groupPath() on iOS.
Fix checkContentChangedByOuterProcess() not working bug.

v2.1.0 / 2025-02-18

Happy Chinese New Year!
This is a breaking change version for the Android/OHOS platform. Read the change log bellow and upgrade carefully.

Changes for All platforms

Add the NameSpace feature that easily supports customizing a root directory.
Add protection from bad disk records of MMKV files.
Fix FileLock not being unlocked on destruction.
Improve directory creation on ReadOnly mode.

Android

Breaking change: Migrate legacy MMKV in a custom directory to normal MMKV. Historically Android/OHOS mistakenly use mmapKey as mmapID, which will be problematic with the NameSpace feature. Starting from v2.1.0, MMKV will try to migrate them back to normal when possible.
It's highly recommended that you upgrade to v2.0.2/v1.3.11 first with forward support of normal MMKV in a custom directory.
Supports using MMKV directly in C++ code.
Improve inter-process locking by using F_OFD_SETLK instead of F_SETLK.
Add experimental protection from bad disk records of MMKV files.

HarmonyOS NEXT

Breaking change: Migrate legacy MMKV in a custom directory to normal MMKV. Historically Android/OHOS mistakenly use mmapKey as mmapID, which will be problematic with the NameSpace feature. Starting from v2.1.0, MMKV will try to migrate them back to normal when possible.
It's highly recommended that you upgrade to v2.0.2/v1.3.11 first with forward support of normal MMKV in a custom directory.
Supports using MMKV directly in C++ code.
Improve inter-process locking by using F_OFD_SETLK instead of F_SETLK.
Add experimental protection from bad disk records of MMKV files.

iOS/macOS

Upgrade to iOS 13, macOS 10.15, and watchOS 6 to support the NameSpace functionality.
Supports using MMKV directly in C++ code.
Drop the background mlock() protection given that we are iOS 13+.
Add tested protection from bad disk records of MMKV files.
Fix a package error when using MMKV by submodule.

Flutter

Remove unused imports and fix deprecated implementations.
Support flutter 3.29.

Win32

Add tested protection from bad disk records of MMKV files.

POSIX

Improve inter-process locking by using F_OFD_SETLK instead of F_SETLK.
Add experimental protection from bad disk records of MMKV files.
Fix a compile error on the GNU toolchain.

Golang

Fix a link error in the armv8 arch.
Improve multi-platform building.

v2.0.2 / 2024-12-27

Mary holiday and a happy new year!

Changes for All platforms

Fix a bug that MMKV might fail to backup/restore across different filesystems.
Add protection from invalid value size of auto-key-expire mmkv.

Android

If the running App is 32-bit only, warn about it (by throwing UnsupportedArchitectureException) before trying to load native lib.
Add forward support for the correct filename with a custom root path.

HarmonyOS NEXT

Obfuscation fully supported.
Use atomic file rename on OHOS.
Add forward support for the correct filename with a custom root path.

Win32

Only mmap() on ftruncate()/zeroFillFile() failure iff we have a valid file mapping before.

v2.0.1 / 2024-11-12

This is a hotfix release.

Changes for All platforms

Fix a bug that might cause MMKV to become dead-locked for other threads after decoding container-type values. The affected platforms and value types are listed below. So don't be surprised if you find no update on the unaffected platforms.

HarmonyOS NEXT

Fix a bug that MMKV might become dead-locked for other threads after decodeStringSet() / decodeNumberSet / decodeBoolSet or decoding TypedArray.

Flutter

Fix the bug on HarmonyOS NEXT listed above. A version named v2.0.1 was added to fix the Android version conflict between the LTS series & v2.0. Thanks to the federated plugins framework, only the underlying mmkv_ohos plugin is upgraded, the mmkv plugin stays the same.

POSIX

Fix a bug that MMKV might become dead-locked for other threads after decoding std::vector<T> or std::span<T> values.

v2.0.0 / 2024-10-21

This release is a breaking change release, especially for Android.

Changes for All platforms

Add readonly mode support.
Fix a compile error when MMKV_DISABLE_CRYPT is defined and MMKV is built by source in DEBUG.

Android

Support 16K page size for Android 15.
Drop the support of 32-bit ABI.
Bump the mini SDK level to API 23.

iOS / macOS

Add Mac Catalyst support

Flutter

Add add log/error/content-change callback.

HarmonyOS NEXT

Add add log/error/content-change callback.
Support obfuscation. For the time being, you will have to manually copy the content of MMKV's consumer-rules.txt into your App's obfuscation-rules.txt.

Win32

Replace random() with rand() to fix a compile error.

v1.3.9 / 2024-07-26

This is a Long Term Support (LTS) release.

Changes for All platforms

Fix a data corruption bug on an encrypted MMKV with only one key value stored.
Make encryption more resilient from brute force cracking.
Fix a bug that pthread_mutex is not being destroyed correctly.

Android

Use an alternative way to get the process name to avoid potential App review issues.
Upgrade to NDK 26.3.11579264.

Flutter

Add support for HarmonyOS NEXT. In fact, a temp version named v1.3.8 adds this support with the native lib of v1.3.7. To avoid potential confusion, bump both versions to v1.3.9.

v1.3.7 / 2024-07-08

Android & Flutter

This Long Term Support (LTS) release primarily reintroduces support for the ARMv7 architecture and lowers the minimum SDK version requirement to 21. Please note that only critical bug fixes will be applied to the 1.3.x series. New features will be introduced in version 2.0 and later, which will discontinue support for 32-bit architectures and raise the minimum SDK version requirement to 23.

For other platforms

This is exactly the same as v1.3.6, so don't be surprised if you don't see this version in CocoaPods or OHPM.

v1.3.6 / 2024-07-05

Changes for All platforms

The Core library now upgrades the C++ standard from C++17 to C++20 to make the most of morden C++ feature such as Concept & unordered containers with std::string_view as key. From now on, if you build MMKV by source (iOS, Windows, POSIX, etc), you will need a C++ compiler that supports the C++20 standard. If you only use MMKV in binary (Android, OHOS, etc), this upgrade of the C++ compiler is not required.
The key type changes from std::string to std::string_view, to avoid unnecessary string construction and destruction when the key is a raw string.

Android

Use the latest ashmem API if possible.
Use the latest API to get the device API level.

Flutter

MMKV will try to load libmmkv.so before Dart code, to reduce the error of loading library in Android.

HarmonyOS NEXT

Fix a bug that a String value might get truncated on encoding.
MMKV returns undefined when a key does not exist, previously a default value of the type (false for boolean, 0 for number, etc) is returned.
Add the feature to encode/decode a float value.
Add the feature to encode/decode a TypedArray value.
Support encoding a part of an ArrayBuffer.

iOS/macOS

Hide the default NSObject.initialize() from Swift/ObjC to prevent potential misuse.

POSIX

Support encode/decode std::vector<T> or std::span<T> values, with T as primitive types.
Fix a compile error on Linux env.
Fix a compile error on the GNU compiler.
Fix a compile error with some old version of zlib (on CentOS).

Python

Python now runs on Windows. Check out the latest wiki for instructions.

Windows

Support encode/decode std::vector<T> or std::span<T> values, with T as primitive types.
Python now runs on Windows. Check out the latest wiki for instructions.

v1.3.5 / 2024-04-24

HarmonyOS NEXT

This is the first official support of HarmonyOS NEXT.
Most things actually work!
Checkout the wiki for more.

Flutter

Migrate to federated plugins to avoid the iOS rename headache. From now on, no more renaming from mmkv to mmkvflutter is needed.
Bump iOS Deployment Target to iOS 12.
Bump Android minSdkVersion to 23.

iOS & macOS

Avoid using so-called privacy APIs (lstat(), fstat(), NSUserDefaults).
Bump iOS Deployment Target to iOS 12.

Android

Bump minSdkVersion to 23.
Drop armv7 & x86 support.

POSIX

Use the embedded libz when libz can not be found.
Fix compile error when building with gcc.

Windows

Support x64 architecture.

v1.3.4 / 2024-03-15

Changes for All platforms

Make trim() more robust in multi-process mode.

iOS & macOS

Support visionOS.

POSIX

Fix a compile error on ::unlink().

v1.3.3 / 2024-01-25

Changes for All platforms

Add removeStorage() static method to safely delete underlying files of an MMKV instance.
Add protection from a potential crash of a multi-process MMKV loading due to the MMKV file not being valid.
Add back the lazy load feature. It was first introduced in v1.2.16. But it was rollbacked in v1.3.0 of potential ANR & file corruption. Now it's clear that the bug was caused by something else, it's time to bring it back.
Optimize loading speed by using shared inter-process lock unless there's a need to truncate the file size, which is rare.
Make these two lately added features more robust: customizing the initial file size & optimizing write speed when there's only one key inside MMKV.

Android

Fix a bug that null is returned when the value is in fact an empty ByteArray.
Fix AGP >= 8 package namespace error.
Fix the FastNative naming conflict.
Upgrade to SDK 34.
Upgrade androidx.annotation to v1.7.1.

iOS & macOS

On the Xcode 15 build, an App will crash on iOS 14 and below. Previously we have recommended some workarounds (check the v1.3.2 release note for details). Now you can use Xcode 15.1 to fix this issue.
Fix a bug that the multi-process mode won't configure correctly. It was introduced in v1.3.2.
Fix a macro naming conflict.
Avoid using a so-called privacy API when creating temp files.

POSIX

Fix a compile error on memcpy().

Golang

Fix a compile error when MMKV_DISABLE_CRYPT is on.

v1.3.2 / 2023-11-20

Among most of the features added in this version, the credit goes to @kaitian521.

Changes for All platforms

Add the feature of customizing the initial file size of an MMKV instance.
Optimize write speed when there's only one key inside MMKV, the new key is the same as the old one, and MMKV is in SINGLE_PROCESS_MODE.
Optimize write speed by overriding from the beginning of the file instead of append in the back, when there's zero key inside MMKV, and MMKV is in SINGLE_PROCESS_MODE.
Add the feature of clearAll() with keeping file disk space unchanged, reducing the need to expand file size on later insert & update operations. This feature is off by default, you will have to call it with relative params or newly added methods.
Add the feature of comparing values before setting/encoding on the same key.
Fix a potential bug that the MMKV file will be invalid state after a successful expansion but a failure zeroFill(), will lead to a crash.
Fix a potential crash due to other module/static lib turn-off RTTI, which will cause MMKV to fail to catch std::exception.
Fix several potential crash due to the MMKV file not being valid.

Android

Use the -O2 optimization level by default, which will reduce native lib size and improve read/write speed a little bit.
Experimantal use @fastNative annotation on enableCompareBeforeCompare() to speed up JNI call.

iOS & macOS

Optimize auto-clean logic to reduce lock waiting time.
Turn-off mlock() protection in background on iOS 13+. We have verified it on WeChat that the protection is no longer needed from at least iOS 13. Maybe iOS 12 or older is also not needed, but we don't have the chance to verify that because WeChat no longer supports iOS 12.

Known Issue

On Xcode 15 build, App will crash on iOS 14 and below. The bug is introduced by Apple's new linker. The official solutions provided by Apple are either:
- Drop the support of iOS 14.
- Add -Wl,-weak_reference_mismatches,weak or -Wl,-ld_classic options to the OTHER_LDFLAGS build setting of Xcode 15. Note that these options are not recognized by older versions of Xcode.
- Use older versions of Xcode, or wait for Xcode 15.2.

v1.3.1 / 2023-8-11

This is a hotfix version. It's highly recommended that v1.2.16 & v1.3.0 users upgrade as soon as possible.

Changes for All platforms

Fix a critical bug that might cause multi-process MMKV corrupt. This bug was introduced in v1.2.16.
Add the ability to filter expired keys on count() & allKeys() methods when auto key expiration is turn on.
Reduce the msync() call on newly created MMKV instances.

iOS & macOS

Fix a bug that NSKeyedArchive object might fail to decode when auto key expiration is turn on.

v1.3.0 / 2023-06-14

Changes for All platforms

Add auto key expiration feature. Note that this is a breaking change, once upgrade to auto expiration, the MMKV file is not valid for older versions of MMKV (v1.2.16 and below) to correctly operate.
Roll back the lazy load optimization due to reported ANR issues. It was introduced in v1.2.16.

iOS & macOS

Fix a potential memory leak on setting a new value for an existing key.
Upgrade min support target to iOS 11 / macOS 10.13 / tvOS 13 / watchOS 4.

Windows

Fix a bug that might fail to truncate the file size to a smaller size in some cases.

Flutter

The version of MMKV for Flutter is now the same as the MMKV native library.
Starting from v1.3.0, Flutter for Android will use com.tencent:mmkv. Previously it's com.tencent:mmkv-static. It's the same as com.tencent:mmkv starting from v1.2.11.

v1.2.16 / 2023-04-20

Changes for All platforms

Optimization: The actual file content is lazy loaded now, saving time on MMKV instance creation, and avoiding lock waiting when a lot of instances are created at the same time.
Fix a bug when restoring a loaded MMKV instance the meta file might mistakenly report corrupted.

Android

Optimization: Remove unnecessary binder call on main process instantiation.

Flutter

Fix a crash on decoding an empty list.
Remove deprecated dependence.
Make the script more robust to fix the iOS Flutter plugin name.

Windows

Fix a string format bug on the MinGW64 environment.

golang

Fix a build error on 32-bit OS.

v1.2.15 / 2023-01-12

Changes for All platforms

Log handler now handles all logs from the very beginning, especially the logs in initialization.
Log handler register method is now deprecated. It's integrated with initialize().
Fix a bug that lock()/unlock()/try_lock() is not thread-safe.

Flutter

Reduce the privacy info needed to obtain android sdkInt, avoid unnecessary risk on Android App Review.

iOS & macOS

Fix a compile error on macOS.
Fix a bug that some ObjC exceptions are not being caught.
Add assert on nil MMKV base path, protect from mis-using MMKV in global variable initialization.
Starting from v1.2.15, one must call +[MMKV initializeMMKV:] manually before calling any MMKV methods.

golang

Fix a compile error on GCC.

Windows

Support CMake project on Windows.

v1.2.14 / 2022-08-10

Changes for All platforms

Fix a bug that MMKV.getXXX() may return invalid results in multi-process mode.

Android

Return [] instead of null on empty StringSet from MMKV.decodeStringSet() methods.
Upgrade Android Compile & Target SDK to 32.

iOS

Protect from the crash in -[MMKV getObject:forKey:] method when the key-value doesn't exist.

v1.2.13 / 2022-03-30

Android

Fix crash on using Ashmem while MMKV_DISABLE_CRYPT macro is defined.

iOS

Add ability to retrieve key existece while getting value, aka -[MMKV getXXX:forKey:hasValue:] methods.

POSIX

Add ability to retrieve key existece while getting value, aka MMKV::getXXX(key, defaultValue, hasValue) methods.

Windows

Add ability to retrieve key existece while getting value, aka MMKV::getXXX(key, defaultValue, hasValue) methods.

v1.2.12 / 2022-01-17

Changes for All platforms

Fix a bug that a subsequential clearAll() call may fail to take effect in multi-process mode.
Hide some OpenSSL symbols to prevent link-time symbol conflict, when an App somehow also static linking OpenSSL.

Android

Upgrade compileSdkVersion & targetSdkVersion from 30 to 31.

v1.2.11 / 2021-10-26

Android

Due to increasing report about crash inside STL, we have decided to make MMKV static linking libc++ by default. Starting from v1.2.11, com.tencent:mmkv-static is the same as com.tencent:mmkv.
For those still in need of MMKV with shared linking of libc++_shared, you could use com.tencent:mmkv-shared instead.
Add backup & restore ability.

iOS / macOS

Add backup & restore ability.
Support tvOS.
Fix a compile error on some old Xcode.

Flutter (v1.2.12)

Add backup & restore ability.

POSIX / golang / Python

Add backup & restore ability.
Fix a compile error on Gentoo.

Windows

Add backup & restore ability.

v1.2.10 / 2021-06-25

This version is mainly for Android & Flutter.

Android

Complete JavaDoc documentation for all public methods, classes, and interfaces. From now on, you can find the API reference online.
Drop the support of armeabi arch. Due to some local build cache mistake, the last version (v1.2.9) of MMKV still has an unstripped armeabi arch inside. This is fixed.
Change MMKV.mmkvWithID() from returning null to throwing exceptions on any error.
Add MMKV.actualSize() to get the actual used size of the file.
Mark MMKV.commit() & MMKV.apply() as deprecated, to avoid some misuse after migration from SharedPreferences to MMKV.

Flutter (v1.2.11)

Bug Fixed: When building on iOS, occasionally it will fail on symbol conflict with other libs. We have renamed all public native methods to avoid potential conflict.
Keep up with MMKV native lib v1.2.10.

v1.2.9 / 2021-05-26

This version is mainly for Android & Flutter.

Android

Drop the support of armeabi arch. As has been mention in the last release, to avoid some crashes on the old NDK (r16b), and make the most of a more stable libc++, we have decided to upgrade MMKV's building NDK in this release. That means we can't support armeabi anymore. Those who still in need of armeabi can build from sources by following the instruction in the wiki.

We really appreciate your understanding.

Flutter (v1.2.10)

Bug Fixed: When calling MMKV.encodeString() with an empty string value on Android, MMKV.decodeString() will return null.
Bug Fixed: After upgrading from Flutter 1.20+ to 2.0+, calling MMKV.defaultMMKV() on Android might fail to load, you can try calling MMKV.defaultMMKV(cryptKey: '\u{2}U') with an encrytion key '\u{2}U' instead.
Keep up with MMKV native lib v1.2.9.

v1.2.8 / 2021-05-06

This will be the last version that supports armeabi arch on Android. To avoid some crashes on the old NDK (r16b), and make the most of a more stable libc++, we have decided to upgrade MMKV's building NDK in the next release. That means we can't support armeabi anymore.

We really appreciate your understanding.

Android

Migrate MMKV to Maven Central Repository. For versions older than v1.2.7 (including), they are still available on JCenter.
Add MMKV.disableProcessModeChecker(). There are some native crash reports due to the process mode checker. You can disable it manually.
For the same reason described above (native crashed), MMKV will now turn off the process mode checker on a non-debuggable app (aka, a release build).
For MMKV to detect whether the app is debuggable or not, when calling MMKV.initialize() to customize the root directory, a context parameter is required now.

iOS / macOS

Min iOS support has been upgrade to iOS 9.
Support building by Xcode 12.

Flutter (v1.2.9)

Support null-safety.
Upgrade to flutter 2.0.
Fix a crash on the iOS when calling encodeString() with an empty string value.

Known Issue on Flutter

When calling encodeString() with an empty string value on Android, decodeString() will return null. This bug will be fixed in the next version of Android Native Lib. iOS does not have such a bug.

Windows

Fix a compile error on Visual Studio 2019.

v1.2.7 / 2020-12-25

Happy holidays everyone!

Changes for All platforms

Fix a bug when calling sync() with false won't do msync() asynchronous and won't return immediately.

Android

Fix an null pointer exception when calling putStringSet() with null.
Complete review of all MMKV methods about Java nullable/nonnull annotation.
Add API for MMKV.initialize() with both Context and LibLoader parammeters.

Flutter (v1.2.8)

Fix a crash on the iOS simulator when accessing the default MMKV instance.
Fix a bug on iOS when initing the default MMKV instance with a crypt key, the instance is still in plaintext.

Golang

Add golang for POSIX platforms. Most things actually work!. Check out the wiki for information.

v1.2.6 / 2020-11-27

Changes for All platforms

Fix a file corruption when calling reKey() after removeKeys() has just been called.

Android

Fix compile error when MMKV_DISABLE_CRYPT is set.
Add a preprocess directive MMKV_DISABLE_FLUTTER to disable flutter plugin features. If you integrate MMKV by source code, and if you are pretty sure the flutter plugin is not needed, you can turn that off to save some binary size.

Flutter (v1.2.7)

Add MMKV support for Flutter on iOS & Android platform. Most things actually work!
Check out the wiki for more info.

v1.2.5 / 2020-11-13

This is a pre-version for Flutter. The official Flutter plugin of MMKV will come out soon. Stay Tune!

iOS / macOS

Fix an assert error of encrypted MMKV when encoding some <NSCoding> objects.
Fix a potential leak when decoding duplicated keys from the file.
Add +[MMKV pageSize], +[MMKV version] methods.
Add +[MMKV defaultMMKVWithCryptKey:], you can encrypt the default MMKV instance now, just like the Android users who already enjoy this for a long time.
Rename -[MMKV getValueSizeForKey:] to -[MMKV getValueSizeForKey: actualSize:] to align with Android interface.

Android

Fix a potential crash when getting MMKV instances in multi-thread at the same time.
Add MMKV.version() method.

v1.2.4 / 2020-10-21

This is a hotfix mainly for iOS.

iOS / macOS

Fix a decode error of encrypted MMKV on some devices.

Android

Fix a potential issue on checking rootDir in multi-thread while MMKV initialization is not finished.

v1.2.3 / 2020-10-16

Changes for All platforms

Fix a potential crash on 32-bit devices due to pointer alignment issue.
Fix a decode error of encrypted MMKV on some 32-bit devices.

iOS / macOS

Fix a potential crc32() crash on some kind of arm64 devices.
Fix a potential crash after calling +[MMKV onAppTerminate].

Android

Fix a rare lock conflict on checkProcessMode().

POSIX

Add MMKV support for Python on POSIX platforms. Most things actually work!
Check out the wiki for more info.

v1.2.2 / 2020-07-30

iOS / macOS

Add auto clean up feature. Call +[MMKV enableAutoCleanUp:] to enable auto cleanup MMKV instances that not been accessed recently.
Fix a potential crash on devices under iPhone X.

Android

Add multi-process mode check. After so many issues had been created due to mistakenly using MMKV in multi-process mode in Android, this check is added. If an MMKV instance is accessed with SINGLE_PROCESS_MODE in multi-process, an IllegalArgumentException will be thrown.

POSIX

Add support for armv7 & arm64 arch on Linux.

v1.2.1 / 2020-07-03

This is a hotfix release. Anyone who has upgraded to v1.2.0 should upgrade to this version immediately.

Fix a potential file corruption bug when writing a file that was created in versions older than v1.2.0. This bug was introduced in v1.2.0.
Add a preprocess directive MMKV_DISABLE_CRYPT to turn off MMKV encryption ability once and for all. If you integrate MMKV by source code, and if you are pretty sure encryption is not needed, you can turn that off to save some binary size.
The parameter relativePath (customizing a separate folder for an MMKV instance), has been renamed to rootPath. Making it clear that an absolute path is expected for that parameter.

iOS / macOS

-[MMKV mmkvWithID: relativePath:] is deprecated. Use -[MMKV mmkvWithID: rootPath:] instead.
Likewise, -[MMKV mmkvWithID: cryptKey: relativePath:] is deprecated. Use -[MMKV mmkvWithID: cryptKey: rootPath:] instead.

v1.2.0 / 2020-06-30

This is the second major version of MMKV. Everything you call is the same as the last version, while almost everything underneath has been improved.

Reduce Memory Footprint. We used to cache all key-values in a dictionary for efficiency. From now on we store the offset of each key-value inside the mmap-memory instead, reducing memory footprint by almost half for (non-encrypt) MMKV. And the accessing efficiency is almost the same as before. As for encrypted MMKV, we can't simply store the offset of each key-value, the relative encrypt info needs to be stored as well. That will be too much for small key-values. We only store such info for large key-values (larger than 256B).
Improve Writeback Efficiency. Thanks to the optimization above, we now can implement writeback by simply calling memmove() multiple times. Efficiency is increased and memory consumption is down.
Optimize Small Key-Values. Small key-values of encrypted MMKV are still cached in memory, as all the old versions did. From now on, the struct MMBuffer will try to store small values in the stack instead of in the heap, saving a lot of time from malloc() & free(). In fact, all primitive types will be store in the stack memory.

All of the improvements above are available to all supported platforms. Here are the additional changes for each platform.

iOS / macOS

Optimize insert & delete. Especially for inserting new values to existing keys, or deleting keys. We now use the UTF-8 encoded keys in the mmap-memory instead of live encoding from keys, cutting the cost of string encoding conversion.
Fix Xcode compile error on some projects.
Drop the support of iOS 8. thread_local is not available on iOS 8. We choose to drop support instead of working around because iOS 8's market share is considerably small.

POSIX

It's known that GCC before 5.0 doesn't support C++17 standard very well. You should upgrade to the latest version of GCC to compile MMKV.

v1.1.2 / 2020-05-29

Android / iOS & macOS / Windows / POSIX

Fix a potential crash after trim() a multi-process MMKV instance.
Improve clearAll() a bit.

v1.1.1 / 2020-04-13

iOS / macOS

Support WatchOS.
Rename +[MMKV onExit] to +[MMKV onAppTerminate], to avoid naming conflict with some other OpenSource projects.
Make background write protection much more robust, fix a potential crash when writing meta info in background.
Fix a potential data corruption bug when writing a UTF-8 (non-ASCII) key.

Android

Fix a crash in the demo project when the App is hot reloaded.
Improve wiki & readme to recommend users to init & destruct MMKV in the Application class instead of the MainActivity class.

POSIX

Fix two compile errors with some compilers.

v1.1.0 / 2020-03-24

This is the first major breaking version ever since MMKV was made public in September 2018, introducing bunches of improvement. Due to the Covid-19, it has been delayed for about a month. Now it's finally here!

Improved File Recovery Strategic. We store the CRC checksum & actual file size on each sync operation & full write back, plus storing the actual file size in the same file(aka the .crc meta file) as the CRC checksum. Base on our usage inside WeChat on the iOS platform, it cuts the file corruption rate down by almost half.
Unified Core Library. We refactor the whole MMKV project and unify the cross-platform Core library. From now on, MMKV on iOS/macOS, Android, Windows all share the same core logic code. It brings many benefits such as reducing the work to fix common bugs, improvements on one platform are available to other platforms immediately, and much more.
Supports POSIX Platforms. Thanks to the unified Core library, we port MMKV to POSIX platforms easily.
Multi-Process Access on iOS/macOS. Thanks to the unified Core library, we add multi-process access to iOS/macOS platforms easily.
Efficiency Improvement. We make the most of armv8 ability including the AES & CRC32 instructions to tune encryption & error checking speed up by one order higher than before on armv8 devices. There are bunches of other speed tuning all around the whole project.

Here are the old-style change logs of each platform.

iOS / macOS

Adds multi-process access support. You should initialize MMKV by calling +[MMKV initializeMMKV: groupDir: logLevel:], passing your app group id. Then you can get a multi-process instance by calling +[MMKV mmkvWithID: mode:] or +[MMKV mmkvWithID: cryptKey: mode:], accessing it cross your app & your app extensions.
Add inter-process content change notification. You can get MMKV changes notification of other processes by implementing - onMMKVContentChange: of <MMKVHandler> protocol.
Improved File Recovery Strategic. Cuts the file corruption rate down by almost half. Details are above.
Efficiency Improvement. Encryption & error checking speed are up by one order higher on armv8 devices(aka iDevice including iPhone 5S and above). Encryption on armv7 devices is improved as well. Details are ahead.
Other speed improvements. Refactor core logic using MRC, improve std::vector push_back() speed by using move constructors & move assignments.
+[MMKV setMMKVBasePath:] & +[MMKV setLogLevel:] are marked deprecated. You should use +[MMKV initializeMMKV:] or +[MMKV initializeMMKV: logLevel:] instead.
The MMKVLogLevel enum has been improved in Swift. It can be used like MMKVLogLevel.info and so on.

Android

Improved File Recovery Strategic. Cuts the file corruption rate down by almost half. Details are above.
Efficiency Improvement. Encryption & error checking speed are up by one order higher on armv8 devices with the arm64-v8a abi. Encryption on armeabi & armeabi-v7a is improved as well. Details are ahead.
Add exception inside core encode & decode logic, making MMKV much more robust.
Other speed improvements. Improve std::vector push_back() speed by using move constructors & move assignments.

Windows

Improved File Recovery Strategic. Cuts the file corruption rate down by almost half. Details are above.
Add exception inside core encode & decode logic, making MMKV much more robust.
Other speed improvements. Improve std::vector push_back() speed by using move constructors & move assignments.

POSIX

Most things actually work! We have tested MMKV on the latest version of Linux(Ubuntu, Arch Linux, CentOS, Gentoo), and Unix(macOS, FreeBSD, OpenBSD) on the time v1.1.0 is released.

v1.0.24 / 2020-01-16

iOS / macOS

What's new

Fix a bug that MMKV will fail to save any key-values after calling -[MMKV clearMemoryCache] and then -[MMKV clearAll].
Add +[MMKV initializeMMKV:] for users to init MMKV in the main thread, to avoid an iOS 13 potential crash when accessing UIApplicationState in child threads.
Fix a potential crash when writing a uniquely constructed string.
Fix a performance slow down when acquiring MMKV instances too often.
Make the baseline test in MMKVDemo more robust to NSUserDefaults' caches.

Android

What's new

Fix flock() bug on ashmem files in Android.
Fix a potential crash when writing a uniquely constructed string.
Fix a bug that the MMKVDemo might crash when running in a simulator.

Windows

Fix a potential crash when writing a uniquely constructed string or data.

v1.0.23 / 2019-09-03

iOS / macOS

What's new

Fix a potential security leak on encrypted MMKV.

Android

What's new

Fix a potential security leak on encrypted MMKV.
Fix filename bug when compiled on Windows environment.
Add option for decoding String Set into other Set<> classes other than the default HashSet<String>, check decodeStringSet() for details.
Add putBytes() & getBytes(), to make function names more clear and consistent.
Add notification of content changed by other process, check the new MMKVContentChangeNotification<> interface & checkContentChangedByOuterProcess() for details.

Windows

What's new

Fix a potential security leak on encrypted MMKV.
Fix CriticalSection init bug.

v1.0.22 / 2019-06-10

iOS / macOS

What's new

Fix a bug that MMKV will corrupt while adding just one key-value, and reboot or clear memory cache. This bug was introduced in v1.0.21.

Android

What's new

Fix a bug that MMKV will corrupt while adding just one key-value, and reboot or clear memory cache. This bug was introduced in v1.0.21.

Windows

What's new

Fix a bug that MMKV will corrupt while adding just one key-value, and reboot or clear memory cache. This bug was introduced in v1.0.21.

v1.0.21 / 2019-06-06

iOS / macOS

What's new

Fix a bug that MMKV might corrupt while repeatedly adding & removing key-value with specific length. This bug was introduced in v1.0.20.

Android

What's new

Fix a bug that MMKV might corrupt while repeatedly adding & removing key-value with specific length. This bug was introduced in v1.0.20.

Windows

What's new

Fix a bug that MMKV might corrupt while repeatedly adding & removing key-value with specific length. This bug was introduced in v1.0.20.

v1.0.20 / 2019-06-05

iOS / macOS

What's new

Fix a bug that MMKV might crash while storing key-value with specific length.
Fix a bug that -[MMKV trim] might not work properly.

Android

What's new

Migrate to AndroidX library.
Fix a bug that MMKV might crash while storing key-value with specific length.
Fix a bug that trim() might not work properly.
Fix a bug that dead-lock might be reported by Android mistakenly.
Using RegisterNatives() to simplify native method naming.

Windows

Fix a bug that MMKV might crash while storing key-value with specific length.
Fix a bug that trim() might not work properly.
Fix a bug that clearAll() might not work properly.

v1.0.19 / 2019-04-22

iOS / macOS

What's new

Support Swift 5.
Add method to get all keys -[MMKV allKeys];
Add method to synchronize to file asynchronously -[MMKV async].
Fix a pod configuration bug that might override target project's C++ setting on CLANG_CXX_LANGUAGE_STANDARD.
Fix a bug that DEFAULT_MMAP_SIZE might not be initialized before getting any MMKV instance.
Fix a bug that openssl's header files included inside MMKV might mess with target project's own openssl implementation.

Android

What's new

Support Android Q.
Add method to synchronize to file asynchronously void sync(), or void apply() that comes with SharedPreferences.Editor interface.
Fix a bug that a buffer with length of zero might be returned when the key is not existed.
Fix a bug that DEFAULT_MMAP_SIZE might not be initialized before getting any MMKV instance.

v1.0.18 / 2019-03-14

iOS / macOS

What's new

Fix a bug that defaultValue was not returned while decoding a NSCoding value.
Fix a compile error on static linking MMKV while openssl is static linked too.

Android

What's new

Introducing Native Buffer. Checkout wiki for details.
Fix a potential crash when trying to recover data from file length error.
Protect from mistakenly passing Context.MODE_MULTI_PROCESS to init MMKV.

Windows

Fix a potential crash when trying to recover data from file length error.

v1.0.17 / 2019-01-25

iOS / macOS

What's new

Redirect logging of MMKV is supported now.
Dynamically disable logging of MMKV is supported now.
Add method migrateFromUserDefaults to import from NSUserDefaults.

Android

What's new

Redirect logging of MMKV is supported now.
Dynamically disable logging of MMKV is supported now.
Note: These two are breaking changes for interface MMKVHandler, update your implementation with wantLogRedirecting() & mmkvLog() for v1.0.17. (Interface with default method requires API level 24, sigh...)
Add option to use custom library loader initialize(String rootDir, LibLoader loader). If you're facing System.loadLibrary() crash on some low API level device, consider using ReLinker to load MMKV. Example can be found in mmkvdemo.
Fix a potential corruption of meta file on multi-process mode.
Fix a potential crash when the meta file is not valid on multi-process mode.

Windows

Redirect logging of MMKV is supported now.
Dynamically disable logging of MMKV is supported now.
Fix a potential corruption of meta file on multi-process mode.

v1.0.16 / 2019-01-04

iOS / macOS

What's new

Customizing root folder of MMKV is supported now.
Customizing folder for specific MMKV is supported now.
Add method getValueSizeForKey: to get value's size of a key.

Android

What's new

Customizing root folder of MMKV is supported now.
Customizing folder for specific MMKV is supported now.
Add method getValueSizeForKey() to get value's size of a key.
Fix a potential crash when the meta file is not valid.

Storing NSString/NSData/NSDate directly by calling setString/getSring, setData/getData, setDate/getDate.
Fix a potential crash due to divided by zero.

Android

What's new

Fix a stack overflow crash due to the callback feature introduced by v1.0.13.
Fix a potential crash due to divided by zero.

Setting nil value to reset a key is supported now.
Rename boolValue(forKey:) to bool(forKey:) for Swift.

Android

What's new

Parcelable objects can be stored directly into MMKV now.
Setting null value to reset a key is supported now.
Fix an issue that MMKV's file size might expand unexpectly large in some case.
Fix an issue that MMKV might crash on multi-thread removing and getting on the same key.

v1.0.13 / 2018-11-09

iOS / macOS

What's new

Special chars like / are supported in MMKV now. The file name of MMKV with special mmapID will be encoded with md5 and stored in seperate folder.
Add callback for MMKV error handling. You can make MMKV to recover instead of discard when crc32 check fail happens.
Add trim and close operation. Generally speaking they are not necessary in daily usage. Use them if you worry about disk / memory / fd usage.
Fix an issue that MMKV's file size might expand unexpectly large in some case.

Known Issues

Setting nil value to reset a key will be ignored. Use remove instead.

Android

What's new

Add static linked of libc++ to trim AAR size. Use it when there's no other lib in your App embeds libc++_shared.so. Or if you already have an older version of libc++_shared.so that doesn't agree with MMKV.
Add implementation 'com.tencent:mmkv-static:1.0.13' to your App's gradle setting to integrate.
Special chars like / are supported in MMKV now. The file name of MMKV with special mmapID will be encoded with md5 and stored in seperate folder.
Add callback for MMKV error handling. You can make MMKV to recover instead of discard when crc32 check fail happens.
Add trim and close operation. Generally speaking they are not necessary in daily usage. Use them if you worry about disk / memory / fd usage.

Known Issues

Setting null value to reset a key will be ignored. Use remove instead.
MMKV's file size might expand unexpectly large in some case.

v1.0.12 / 2018-10-18

iOS / macOS

What's new

Fix mlock fail on some devices
Fix a performance issue caused by mistakenly merge of test code
Fix CocoaPods integration error of macOS

Android / 2018-10-24

What's new

Fix remove() causing data inconsistency on MULTI_PROCESS_MODE

v1.0.11 / 2018-10-12

iOS / macOS

What's new

Port to macOS
Support NSCoding
You can store NSArray/NSDictionary or any object what implements <NSCoding> protocol.
Redesign Swift interface
Some performance improvement

Known Issues

MMKV use mmapID as its filename, so don't contain any / inside mmapID.
Storing a value of type A and getting by type B may not work. MMKV does type erasure while storing values. That means it's hard for MMKV to do value-type-checking, if not impossible.

Android

What's new

Some performance improvement

Known Issues

Getting an MMKV instance with mmapID that contains / may fail.
MMKV uses mmapID as its filename, so don't contain any / inside mmapID.
Storing a value of type A and getting by type B may not work.
MMKV does type erasure while storing values. That means it's hard for MMKV to do value-type-checking, if not impossible.
registerOnSharedPreferenceChangeListener not supported.
This is intended. We believe doing data-change-listener inside a storage framework smells really bad to us. We suggest using something like event-bus to notify any interesting clients.

v1.0.10 / 2018-09-21

Initial Release