I can't find any information about the status of IMAP version 4 and how widely it's used nowadays and how widely other versions, 1, 2 and 3 are used. So is IMAP version 4 common these days? What about other the versions 1, 2 and 3?
IMAP -- what are the most popular versions used these days?
email;imap
Restricting this to the commonly used Linux servers:CourierCyrusDovecotThey all support IMAP4, since the IMAP4rev1 RFC was defined more than 10 years ago, I don't think you'll find the older version still being used.