I left the tooltip as currently is when offline e.g. Changing WP version requires an internet connection because I thought it is fitting but we can refine it if we consider this necessary.

Have you considered treating it as an error and disable the button if the version is not latest and is offline? All of this behavior is an edge case, but I could see a scenario where the connection fails for a short time and we change the version without the user noticing it. Having an error would make it more visible.

I am in two minds about this because we sort of block the changing of versions already when editing site instead of allowing the user to trigger the error. Perhaps, a middle ground could be to change the tooltip to something like "You are currently offline and can create a site only with the latest version. Selecting a different version requires an internet connection".

Alternatively, we can also source more opinions. On my end, I don't have a strong preference.

I like that suggestion!
Just to confirm that I understood correctly, we would adjust the tooltip as you suggested, and on submission always use the latest version if the user is offline, is that correct?

Just to confirm that I understood correctly, we would adjust the tooltip as you suggested, and on submission always use the latest version if the user is offline, is that correct?

Yeah exactly!