Upgrade to Ubuntu 20 and MySQL 8

Create snapshot or GENERAL backup

Update to uContact >= 3.682
Verify Database for MySQL 8 Upgrade.
mysqlcheck -u root -p --all-databases --check-upgrade

If every chart looks ok, then, within:

/etc/mysql/mysql.conf.d/mysqld.cnf
Delete: NO_AUTO_CREATE_USER
Delete: query_cache_limit y query_cache_size

If you want to see more details:

wget https://dev.mysql.com/get/Downloads/MySQL-Shell/mysql-shell_8.0.26-1ubuntu18.04_amd64.deb
dpkg -i mysql-shell_8.0.26-1ubuntu18.04_amd64.deb
mysqlsh
JS> util.checkForServerUpgrade('usuario@localhost:3306',{"configPath":"/etc/mysql/mysql.conf.d/mysqld.cnf"})

3. Update Operating System.

Yes to restart services and leave the defaults that suggests (just press enter). Select yes to remove the packages that are no longer useful.

4. Install new dependencies.

5. New MySQL 8 driver for UnixODBC.

6. Rebuild Asterisk with new dependencies.

7. Reboot and check.