After updating to IOS 16.2 on my iPad the mail files (inbox, sent, trash)are all screwed up. Can I revert back to previous IOS?

Rolling-back to an earlier version of iOS/iPadOS is not possible.

All System Updates are digitally signed by Apple - and can only be installed whilst the digital signatures remain valid. After release of a new iOS/iPadOS version, the immediately preceding version continues to be digitally signed by Apple - however, usually within a few days, Apple will revoke the digital certificate with which the earlier version is signed.

Deleting and re-adding your email account is sometimes the easiest way to resolve a problem with a specific Mail account. Provided that you are using an IMAP mail service, nothing will be lost - as all your mail is kept on your mail-provider’s mail server.

After deleting the account, perform a forced restart before re-adding the email account to your iPad.

• Delete account:

Settings > Mail > Accounts > [Your Mail Account] > Delete Account

• Force restart the iPad:

Force restart iPad - Apple Support

• Add Mail Account:

Settings > Mail > Add Account