A new APK was just published on F-Droid for 1.0.beta12. This and the 1.0.beta13 release that will be published tomorrow-ish both contain a pretty bad crash which happens every time you open the post creation view.
I suggest to not upgrade until 1.0.beta14 comes out (which I just published so it should be built by F-Droid around Monday I would say).
Sorry about the bad release :(
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