I am not sure if that’s a sync issue or some generic one.
Feel free to move it to the right category.
So, I have a pretty old email account with 10+ years of history.
But Mailspring can show emails only for the last 2 years for some reason.
This is the most “scrollable” history I could ever get.
Then, if I go to the web UI (mailbox), it’s able to show the first messages up to 2012.
Mailspring version is 1.23. Generic IMAP connection (mailbox provider).