Tools/Account Settings/Synchronisation and Storage
Checkbox 'Keep messages etc". Look in Advanced and check the folders you want.
Repeat for each account you have.
I also use Mozbackup to easily make a backup file.
Samsung Galaxy S8 review
1995-2015: How technology has changed the world in 20 years
This poetic animation about monsters is illustrated in a Van Gogh painterly style
Apple predictions 2017
Synology invites you to visit them at Insomnia on 26th – 29th August. Book your tickets now and visit Synology.