If you haven't upgraded in awhile, you'll see some a visual refresh and plenty of little bug fixes. More importantly for some, it also fixes compatibility with mysqueezebox.com on modern Android devices. You can read about all of the changes in the complete changelog.
We've been slowly staging builds for the past few weeks but that effort is mostly completed and now work will shift to the long-idle 'preview' branch, which will be available as an opt-in beta at some time in the future. We appreciated the feedback as we worked through a backlog to get the production version of the app stable on modern devices.
This release is available for Android 4.1 and higher, however the stores will still distribute older releases to older devices, as appropriate.