download the last version for iphoneCoolutils Total Mail Converter Pro 7.1.0.617

I was perplexed at this – not to mention very annoyed, as this is most definitely not how we had our email set up. In any event, suddenly, after the iOS 13 update, the inboxes on our devices running that system were overflowing with hundreds of old email messages. IMAP is not necessarily an improvement from the user's standpoint, although it may well be one if taking the corporate view.

It's been getting harder and harder to maintain this, but it's what worked well for us. AT&T/Yahoo did still allow this if you knew how to set up the email. AT&T/Yahoo has been trying to get everyone to switch to IMAP from POP for some time, but due to our method of archiving email on our Macs, we resisted and keep using POP.

These email accounts were with AT&T/Yahoo and are quite old.

Our iPhone and iPad settings were to 'Keep mail on the server' just as the OP stated. My wife did use her iPhone and iPad to read mail my iPhone was set up, but set to check for mail manually. Prior to iOS 13, we mainly used our desktop Macs to manage our email. We are seeing the same problem as the OP. My wife and I just installed iOS 13 on our iPhones and one iPad. I'm an 'I have this question too' poster.

Download the last version for iphoneCoolutils Total Mail Converter Pro 7.1.0.617