Kodi 18: use 'master' branch: https://github.com/maxbambi/plugin.video.raitv/archive/master.zip
Note: Kodi 18 version of plugin is not fully supported. I have tried to merge new fixes also in this version, but something could not work well
Kodi 19 or more: use 'matrix' branch: https://github.com/maxbambi/plugin.video.raitv/archive/matrix.zip
NOTE: There are known problems when we want to play DRM protected contents. A crash with last version of widevine is solved with a recent update of inputstream adaptive - but this update is available only with kodi 21 (vers. 21.5.13) or 22 (vers. 22.2.3) - , but the issue with Raiplay remains.