When I added a new IMAP folder I wanted to set the expire date for "Expire unread messages after" to 90 days. After saving the value and checking again, I suddenly had a value of 21926 days. Checking my other folders this wrong value was set, too - at least something near it, like 22034 or so. There seems to be another problem with the expire settings - the folder where expired messsages should be stored are gone after saving the value, too. Reproducible: Always
Please report the issue upstream.
(In reply to Andreas Sturmlechner from comment #1) > Please report the issue upstream. Done - https://bugs.kde.org/show_bug.cgi?id=412150