Moving from POP to IMAP is something you have to do with care, since by default POP is based on storing everything on your Mac.Make sure to backup your Users - Mail and Mail Downloads folders if you are using Apple Mail before upgrading. For that you will need to go to Old Mac OS X Speed.As much as possible my software update page includes the most recent security updates indicated below.For updated downloads, visit my Jaguar and Up page This information is available on Apple's Sierra Requirements page Same minimum system requirements exist under Mac OS X 10.8 and later.
As a result an update may appear on the surface to be bad, but in reality a contributing factor is causing your problem.Software tested before that date may not work with the operating system. issues have been reported on Apple Support Communities.IMAP e-mail is by default server based, and if you trust your internet provider to back it up, may be a better solution.Note: this only matters if you already purchased the Sierra download before High Sierra's release.On January 25, 2018 Apple released a security update.
Do not trust those reports, until those reports are published after the official release of Sierra.