I wrote a popular open source IMAP library in 2009 and even then the UID capability was there and widely adopted. My library relied on it 100%, completely ignoring sequence numbers, and I haven't received a single issue related to this.
It's not that new, it's not a hail mary, and it is very well supported.
It's not that new, it's not a hail mary, and it is very well supported.
* https://packagist.org/packages/tedivm/fetch
* https://github.com/tedious/Fetch