@armin @mwl
Mail client? Thunderbird of course, available for MacOS. There might be a iOS version; Thunderbird took over K9 mail client as I recall. Don't use iOS myself so not sure if if K9/Tb are available.

@sirwumpus @mwl Thunderbird is available for macOS - correct.
Sadly it's not available for iOS right now - according to @thunderbird there might be a testable version by the end of the year.

@sirwumpus @mwl @thunderbird Not as far as I know.

@armin @sirwumpus @mwl That's correct - K-9 Mail was only ever on Android. And yes, the current plan is to have alpha code available by the end of the year for the iOS app - we'll keep everyone updated here on our progress!