Trouble upgrading OpenHab 2.5.11

[rossko57]

@GeorgeCostanza

The repository 'https://dl.bintray.com/openhab/apt-repo2 stable Release' no longer has a Release file

This looks relevant

openHAB 2.5.x and the sunset of Bintray

All, The sunset of Bintray on May 1st caused existing openHAB 2.5.x installations to no longer be able to download add-ons from the remote repository (because this was actually Bintray). The original plan was to move this content to another place and offer a seamless switch for the users, but unfortunately this turned out to be more complicated than thought, so that it didn’t work out - at least until now. There are two options to fix the problem, though: Use the offline version of the add-…