A newer Windows 10 Mobile / PC Anniversary update or Redstone 1 CU build has appeared on BuildFeed. Build 14393.221 that has shown up now, is a good jump over the last Anniversary update release build in terms of Build number. It may bring lots of fixes and improvements for issues faced with the Anniversary update.
We last reported about the release of Windows 10 Mobile Build 14393.189 as the Anniversary update CU build for everyone. It was later released to Release Preview Ring too. We also reported about Windows 10 Mobile Build 14393.206 appearing on BuildFeed.
Build 14393.221 has been compiled on September 20. Though it may or may not be released to non-insiders, as by next month we may see more release candidates emerging. It may be headed to Slow / Release Preview Rings however for testing and feedback.