Good news everyone !
The testing branch upgrading the app to 6.1.x seems ready for release, though personally I don’t know anything about this app
You can try this testing branch with : sudo yunohost app upgrade firefly-iii -u https://github.com/YunoHost-Apps/firefly-iii_ynh/tree/testing
Feel free to report any positive/negative feedback so we can hopefully merge this at some point
Hey! I did update my firefly installation to the testing branch with this method a couple of days back and have not had any issues since.
been using the testing branch for a couple of month now without any issues. one thing to watch out for is not all firefly data importer versions are compatible to the main app.
Hello,
For information, I have the same issue with the stable branch but not with the testing.
Thx aleks !
Hello,
It’s Work for Firefly but when I try to connect Firefly III Data Import Tool, I have
Whoops! 500 :(
Sorry, the Firefly III Data Importer broke down.
Error message
JSON exception when decoding response: Syntax error
More information
The error occurred in /var/www/firefly-iii-di/app/Http/Controllers/TokenController.php:115.
Edit:
Well if you have this message check that your application is indeed accessible to visitors.
Problem fixed.
Hi all. Would it be possible to update Firefly to the latest version, since it fixes quite few important breakages ?
Thank you!
Sorry for asking again.. 
but is this project maintained? It seems that the latest version fails in one area after the pull request.