The following "migration" notes didn't work fine when upgrading to v. 1.5.0 from v. 1.4.11. When running the
installto.sh script I got a couple of error concerning the database schema:
ERROR: Error in DDL upgrade 2020020101:  Can't DROP 'user_id_fk_cache_index'; check that column/key exists
This was very annoying. I cured it manually installing all the database foreign keys. Look at this page for more info. I also had to create the 'contactgroupmembers', but I think it would be created by the script in case of no errors.
I solved this one upgrading my mariadb from 10.0 to 10.5
ERROR: Error in DDL upgrade 2020091000:  Index column size too large. The maximum column size is 767 bytes.
So, for what concerns this major update, it could be better for most of us to perform a clean installation.
I'm leaving the following "upgrade" notes for future upgrades, hoping that they may remain valid.
Read the release note at https://github.com/roundcube/roundcubemail/blob/master/CHANGELOG.md for more info.
NB: you have to enable the pdo support to mysql compilng your php --with-pdo-mysql