@jeancf@apps Long tap is used for boosting on another account which is something I use all the time. Long tap reply works the same way which is very handy too.
In recent versions of F-Droid after adding the repo you have to make sure to also have it set as the "preferred" one for the given app.
Also, make sure to export your settings, you'll probably have to do the uninstall/reinstall dance when you switch over since the two repos sign with different keys.
@aaribaud You could add the Fedilab repo to your F-Droid to get the updates directly from there. You can find the repo link in the FAQ section of the Fedilab web site.