From terminal log:
Aborting downgrade from (at least) 10.1 to 5.7. If are sure you want to downgrade to 5.7, remove the file /var/lib/mysql/debian-*.flag and try installing again.
From terminal log:
Aborting downgrade from (at least) 10.1 to 5.7. mysql/debian- *.flag and try installing again.
If are sure you want to downgrade to 5.7, remove the file
/var/lib/