The Windows Insider app for phones has received another update, just a few days after the last one, and again there is no change log in sight. This update appears to be showing for those already on a Windows 10 mobile preview, but not for users still on Windows 8.1. Several users are reporting improved local language support within the app, though there is nothing official from Microsoft about how far that expanded. In addition to some bug fixes, and likely performance enhancements, there is now an option to leave the Windows Insider program from within the app as well.
This app allows you to download pre-release software from Microsoft, as well as give feedback, collect data, and add comments. If you are not already a member of the Insider program, you can sign up at the link below.