I love Thunderbird and it has replaced Outlook (classic) for me, but there's one feature I miss, AutoArchive. In Outlook (classic), emails older than x days can be automatically moved out of the server folders and into local folders, freeing up server storage space and negating the need to pay for additional cloud storage. Thunderbird has the ability to select a group of messages in any folder and right-click > Archive (move) them to the matching Local Folder: perfect! But manually selecting multiple messages older than x days in multiple IMAP folders and selecting "Archive" is a chore too far. Thunderbird should natively have the ability to (optionally) iterate across all IMAP folders and "Archive" any message older than x days, according to the Message Archives setting in Account Settings > Copies & Folders. The Disk Space setting in Account Settings could be an ideal place to add an "Archive messages more than x days old" option, since it already has a "Delete messages more than x days old" option. Note: I know about the AutoarchiveReloaded add-on, but for something as important as shifting emails around with the possible breakage that could occur, and the possibility of the add-on being discontinued, native support would be very much welcome. Another note: this has of course been raised on bugzilla,[1] but it's a 15 year old bug and seemingly unlikely to come to fruition. [1] https://bugzilla.mozilla.org/show_bug.cgi?id=536169