Microsoft last released Windows 10 Mobile Build 14393.3 as cumulative update build to Insiders in Fast Ring. The Build 14393.3 brings some fixes over the RTM Build 14393. You can read all about the Windows 10 Mobile Build 14393.3 by clicking here and about Windows 10 Build 14393.3 by clicking here.
Now a new Windows 10 Build 14393.5 shows up on Buildfeed and has also leaked in a screenshot posted on Twitter. The Build has been compiled on July 21 and may be the next after Build 14393.3 for both PC and Mobile.
Microsoft has announced August 2 as the Windows 10 Anniversary update release date and you can read the massive Windows 10 Mobile changelog & hands-on impressions by clicking here.