Windows 10 insider build 14388 is now rolling out to Slow ring insiders. A few days ago, build 14388 was released for Fast ring insiders. Build 14388 for Slow Ring includes minor improvements and bug fixes. Slow ring insider can now check there updates for latest build. Dona Sarkar informed insiders about the new build.
— Dona Sarkar (@donasarkar) July 15, 2016
Today, insider team also released Windows 10 insider build 14390 for fast ring insiders. Which is most probably Windows 10 Anniversary Update RTM.