Welcome! This forum has a treasure trove of great info – Scouters helping Scouters! Just a heads up, though - all content, information, and opinions shared on this forum are those of the author, not the BSA.
Looking through some old Scout paperwork, I see that our District used to send us annual rosters. This is an extremely useful tool to see what Scouts were in the Troop at a given time.
Is there any way to generate reports of past rosters? It seems that when a Scout leaves, his record is deleted from Scoutbook, which makes it rather difficult to contact him to ask him to rejoin!
It’s also important for other purposes, such as who is eligible for, say, JTE awards.
I’m not aware of a way to recover old roster states unless you exported information contemporaneously.
I had taken to exporting a troop roster more-or-less quarterly when I was our Scoutbook admin, including parent contact info and scout birthdays/ages (can’t recall which was available in the roster builder) so I knew who aged-out when and was no longer eligible, had a way to contact folks when Scoutbook was down. etc.
Records are not deleted in Scoutbook. Memberships (for youth) or positions (for adults) are ended, and that will remove the individual from a unit’s roster in Scoutbook.
In my.scouting.org under Roster → Reports there is a non-renewed membership report. You may need to click on Filter and change the dates so that it spans your recharter date.