See all tickets marked for the 5.15.1 release

Fixes

• Ensure the Downloader and DownloaderOperation callback the completion in atomic and never miss one #3477
• • This fix a long-term issue when multiple download request for same URL at the same time, some callbacks will missing. After fix, this will cause a brand new HTTP request but never miss any callbacks.
• Fix the issue the fallback logic of ImageIO Source should avoid passing any UTI hint #3473
• Try to fix the SDAsyncBlockOperation's race condition #3479 #3275
• Avoid compiler generate the wrong property attribute with non-atomic #3474

Performance

• Remove the unused extra copy for SDAnimatedImage data initializer #3480