Very important note

During GLPI normal operation, if at any time you add a plugin (I mean not 'Timezones', but any others) to your GLPI instance, and if this plugin install tables with DATETIME fields, then automatically the 'Timezones' plugin will be disabled, and before enabling it again, you'll need to re-execute the updatedb.php script.

See: Installation - Execute dbupdate.php script

The existing backups in 'glpi_plugin_timezones_dbbackups' will not be replaced, the new converted tables will be added as new records.