Microsoft today released its first Redstone 3 build for phones, bringing the build number to 15204. Here's what got fixed, improved, and is still listed as a known issue for the build.
Build 15204 RSS
Microsoft has announced the rollout of Windows 10 Mobile build 15204 to the Fast ring - but it also said that just 13 handsets will officially receive the Creators Update when it rolls out next week.