[Caithness]

I think I understand the table structures but I'd appreciate confirmation or correction.

I'm moving from a RPi3 to a RPi4 (both running under LibreElec) and a new HDD. I'm going to take the opportunity to tidy things up so I'm not doing a backup and restore. The disk/file structure is also going to change a bit (moving from partitions to folders) so tables will not be directly comparable. I do want to preserve the watched status and what I'm planning on doing is:

1. install the new sources and update the library on the RPi4
2. backup the RPi3
3. backup the RPi4
4. copy backups to Windows machine
5. extract movies database from ach
6. run through the movie table in MyVideos121.db and find title in MyVideos116.db
7. use that to copy the LastPlayed data fom files in MyVideos116.db to MyVideos121.db
8. return MyVideos121.db  to the backup
9. copy backup to RPi4 and restore

I think that should work but whilst I can't see anything else in the table schema that I think needs to be altered I'm happy to be corrected.

[Klojum]

Don't change things just yet...
Use your old setup, enable watch and resume statuses in the advancedsettings.xml file, restart the old Kodi, and do a Video Export using separate files so that nfo files are created with the watched status.

Now setup your new database with new sources in Kodi 20, and with those nfo files you can scrape your movies/tvshows into your new setup including the watched/resume statuses.

If you want to cherrypick your movies from your old database and transfer data manually into the new database, then you really found yourself some occupational therapy.

[Caithness]

Thanks - I've seen the Export / Import bit before but didn't realise it would do that. I shall explore further.

[Caithness]

Haven't tried the import side yet but the export looks good, apart from the 11 Brother Scan & Cut tutorials which have no jpg or nfo files and the 351 which have duff (<Title> not ,title>) nfo files. The other 6,500 are fine. Should save quite a bit of work - thanks.