The database_server role installs and configures MariaDB database server, which can then be used as database storage by any application.

Amongst other items, the role takes care of configuring the default encoding, collation etc, trying to set sane defaults. At the moment this means using the legacy utf8 encoding. However, this encoding has long been considered deprecated since it cannot properly handle all the characters normally provided by modern Unicode (such as a bunch of different smileys etc).

In order to improve compatibility and allow wider range of Unicode characters to be used, a switch to utf8mb4 encoding (and related collation etc) are required.

Unfortunately, this will be a non-trivial operation, and might require manual process and downtime to ensure correctness during the upgrade.

The following should be done:

• Update the database_server and database roles.
  • Switch from using utf8 to using the utf8mb encoding and collation.
• Update role reference documentation.
  • Document the upgrade process for existing databases. Emphasize that the operation is non-trivial, and that it requires downtime.
• Update usage instructions.
• Update release notes.