We have released version 3.1.1, mainly with bug fixes.
So, did you have feeds that wouldn't refresh because of this error: Feed Download completed but size does not equal expected size?
Then be sure to update to the latest version when it's available to you!
(Side note, if you get it from F-Droid: the build is failing, but we trust that the team will address this and that this release will soon be available for download.)
