Going one more step towards the Windows 10 Creators Update, Microsoft released one more build for Windows Insiders in the fast ring. This build consists no new features other than the bug fixes. The build 15055 is available for both PC and Mobile devices.
A lot of issues have been fixed in this flight, also has few known issues. Before installing it, you should read them carefully.
This build changed the Windows 10 PC version no. to: 1703 and also removed the 'Insider Preview' text from the desktop watermark but the expiration date is still there. Apart from these important changes, there are a set of fixes in this build.
You can check the original blog post published by Dona Sarkar to know more about other changes and fixes in this build. Don't forget to check the 'Known Issues' section too.