In addition to lots of bug fixes, here are the major changes in this release:

General:

• Added support for PS5 DualSense and Xbox Series X controllers to the HIDAPI controller driver
• Added game controller button constants for paddles and new buttons
• Added game controller functions to get additional information:
• SDL_GameControllerGetSerial()
• SDL_GameControllerHasAxis()
• SDL_GameControllerHasButton()
• SDL_GameControllerGetNumTouchpads()
• SDL_GameControllerGetNumTouchpadFingers()
• SDL_GameControllerGetTouchpadFinger()
• SDL_GameControllerHasSensor()
• SDL_GameControllerSetSensorEnabled()
• SDL_GameControllerIsSensorEnabled()
• SDL_GameControllerGetSensorData()
• SDL_GameControllerRumbleTriggers()
• SDL_GameControllerHasLED()
• SDL_GameControllerSetLED()
• Added the hint SDL_HINT_JOYSTICK_HIDAPI_PS5 to control whether the HIDAPI driver for PS5 controllers should be used.
• Added joystick functions to get additional information:
• SDL_JoystickGetSerial()
• SDL_JoystickRumbleTriggers()
• SDL_JoystickHasLED()
• SDL_JoystickSetLED()
• Added an API to allow the application to create virtual joysticks:
• SDL_JoystickAttachVirtual()
• SDL_JoystickDetachVirtual()
• SDL_JoystickIsVirtual()
• SDL_JoystickSetVirtualAxis()
• SDL_JoystickSetVirtualButton()
• SDL_JoystickSetVirtualHat()
• Added SDL_LockSensors() and SDL_UnlockSensors() to guarantee exclusive access to the sensor list
• Added SDL_HAPTIC_STEERING_AXIS to play an effect on the steering wheel
• Added the hint SDL_HINT_MOUSE_RELATIVE_SCALING to control whether relative motion is scaled by the screen DPI or renderer logical size
• The default value for SDL_HINT_VIDEO_MINIMIZE_ON_FOCUS_LOSS is now false for better compatibility with modern window managers
• Added SDL_GetPreferredLocales() to get the application's current locale setting
• Added the hint SDL_HINT_PREFERRED_LOCALES to override your application's default locale setting
• Added SDL_OpenURL() to open a URL in the system's default browser
• Added SDL_HasSurfaceRLE() to tell whether a surface is currently using RLE encoding
• Added SDL_SIMDRealloc() to reallocate memory obtained from SDL_SIMDAlloc()
• Added SDL_GetErrorMsg() to get the last error in a thread-safe way
• Added SDL_crc32(), SDL_wcscasecmp(), SDL_wcsncasecmp(), SDL_trunc(), SDL_truncf()
• Added clearer names for RGB pixel formats, e.g. SDL_PIXELFORMAT_XRGB8888, SDL_PIXELFORMAT_XBGR8888, etc.

Windows:

• Added the RAWINPUT controller driver to support more than 4 Xbox controllers simultaneously
• Added the hint SDL_HINT_JOYSTICK_RAWINPUT to control whether the RAWINPUT driver should be used
• Added the hint SDL_HINT_JOYSTICK_HIDAPI_CORRELATE_XINPUT to control whether XInput and WGI should be used to for complete controller functionality with the RAWINPUT driver.

macOS:

• Added the SDL_WINDOW_METAL flag to specify that a window should be created with a Metal view
• Added SDL_Metal_GetLayer() to get the CAMetalLayer backing a Metal view
• Added SDL_Metal_GetDrawableSize() to get the size of a window's drawable, in pixels

Linux:

• Added Vulkan support to the KMSDRM video driver
• Added the hint SDL_HINT_AUDIO_DEVICE_APP_NAME to specify the name that shows up in PulseAudio for your application
• Added the hint SDL_HINT_AUDIO_DEVICE_STREAM_NAME to specify the name that shows up in PulseAudio associated with your audio stream
• Added the hint SDL_HINT_LINUX_JOYSTICK_DEADZONES to control whether HID defined dead zones should be respected on Linux
• Added the hint SDL_HINT_THREAD_PRIORITY_POLICY to specify the thread scheduler policy
• Added the hint SDL_HINT_THREAD_FORCE_REALTIME_TIME_CRITICAL to allow time critical threads to use a realtime scheduling policy

Android:

• Added SDL_AndroidRequestPermission() to request a specific system permission
• Added the hint SDL_HINT_ANDROID_BLOCK_ON_PAUSE_PAUSEAUDIO to control whether audio will pause when the application goes intot he background

OS/2:

• Added support for OS/2, see docs/README-os2.md for details

Emscripten (running in a web browser):

• Added the hint SDL_HINT_EMSCRIPTEN_ASYNCIFY to control whether SDL should call emscripten_sleep internally