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

General:

• Added SDL_GetTextureScaleMode() and SDL_SetTextureScaleMode() to get and set the scaling mode used for a texture
• Added SDL_LockTextureToSurface(), similar to SDL_LockTexture() but the locked area is exposed as a SDL surface.
• Added new blend mode, SDL_BLENDMODE_MUL, which does a modulate and blend operation
• Added the hint SDL_HINT_DISPLAY_USABLE_BOUNDS to override the results of SDL_GetDisplayUsableBounds() for display index 0.
• Added the window underneath the finger to the SDL_TouchFingerEvent
• Added SDL_GameControllerTypeForIndex(), SDL_GameControllerGetType() to return the type of a game controller (Xbox 360, Xbox One, PS3, PS4, or Nintendo Switch Pro)
• Added the hint SDL_HINT_GAMECONTROLLERTYPE to override the automatic game controller type detection
• Added SDL_JoystickFromPlayerIndex() and SDL_GameControllerFromPlayerIndex() to get the device associated with a player index
• Added SDL_JoystickSetPlayerIndex() and SDL_GameControllerSetPlayerIndex() to set the player index associated with a device
• Added the hint SDL_HINT_GAMECONTROLLER_USE_BUTTON_LABELS to specify whether Nintendo Switch Pro controllers should use the buttons as labeled or swapped to match positional layout. The default is to use the buttons as labeled.
• Added support for Nintendo GameCube controllers to the HIDAPI driver, and a hint SDL_HINT_JOYSTICK_HIDAPI_GAMECUBE to control whether this is used.
• Improved support for Xbox 360 and Xbox One controllers when using the HIDAPI driver
• Added support for many game controllers, including:
  • 8BitDo FC30 Pro
  • 8BitDo M30 GamePad
  • BDA PS4 Fightpad
  • HORI Fighting Commander
  • Hyperkin Duke
  • Hyperkin X91
  • MOGA XP5-A Plus
  • NACON GC-400ES
  • NVIDIA Controller v01.04
  • PDP Versus Fighting Pad
  • Razer Raion Fightpad for PS4
  • Razer Serval
  • Stadia Controller
  • SteelSeries Stratus Duo
  • Victrix Pro Fight Stick for PS4
  • Xbox One Elite Series 2
• Fixed blocking game controller rumble calls when using the HIDAPI driver
• Added SDL_zeroa() macro to zero an array of elements
• Added SDL_HasARMSIMD() which returns true if the CPU has ARM SIMD (ARMv6+) features

Windows:

• Fixed crash when using the release SDL DLL with applications built with gcc
• Fixed performance regression in event handling introduced in 2.0.10
• Added support for SDL_SetThreadPriority() for UWP applications

Linux:

• Added the hint SDL_HINT_VIDEO_X11_WINDOW_VISUALID to specify the visual chosen for new X11 windows
• Added the hint SDL_HINT_VIDEO_X11_FORCE_EGL to specify whether X11 should use GLX or EGL by default

iOS / tvOS / macOS:

• Added SDL_Metal_CreateView() and SDL_Metal_DestroyView() to create CAMetalLayer-backed NSView/UIView and attach it to the specified window.

iOS/ tvOS:

• Added support for Bluetooth Steam Controllers as game controllers

tvOS:

• Fixed support for surround sound on Apple TV

Android:

• Added SDL_GetAndroidSDKVersion() to return the API level of the current device
• Added support for audio capture using OpenSL-ES
• Added support for Bluetooth Steam Controllers as game controllers
• Fixed rare crashes when the app goes into the background or terminates