about 2 years ago - SLG-Dennis - Direct link
If you play via Steam and it asks you for login data, there is an issue with Steam (restart it) or with your internet connection (make sure it's on). You don't need a SLG account to login for it and your SLG account probably won't work either, as staging runs on a staging database that is not regularly synced with production, hence your SLG account may not be on it yet.

Also note, that in case you wanted to participate in playtest, the "playtest" branch would be the correct one, not "staging".
about 2 years ago - SLG-Dennis - Direct link
Playtest unfortunately only supports the steam version at this time. (You can connect to it, if you know the exact build number, though. Currently it's 2240.)
about 2 years ago - SLG-Dennis - Direct link
You still can, by just downloading the respective staging version, currently it's 2246.
about 2 years ago - SLG-Dennis - Direct link
You need to open the older builds on the website, and then download the staging version I mentioned, you will not be able to use newer versions, as playtest is updated separately.

No, changelogs for staging versions are not published.