Just for somebody who might face a language update problems
The Joomla (3.8.10) message when trying to install a new languageThe update table is not up to date. Please rebuild your update server table. No matching results.
leading to another error when updating server tableDatabase error - You have an error in your SQL syntax; check the manual that corresponds to your MySQL server version for the right syntax to use near '' at line 3
Disabling RokUpdater solved the database error. Recurring "please rebuild" is solved in my case with another, not RokUpdater-related actions.
So not only RokUpdater plugin is no longer required... see a mRT answer to another postUninstall rokupdater completely - it is no longer required as all our extensions are free.
... But probably not recommended to be installed
Thanks