Gridbox update from version 1.2.9

Running Joomla! 3.10.12 and using Gridbox 1.2.9, need to update both Joomla! and Gridbox to newest version. When I try to update Gridbox it crashes, I did try update to version 2.3.1 but no luck, I don't have older version by hand.

So the question is, what is the correct process to update Joomla! and Gridbox to newest versions from version 3.10.12 and Gridbox 1.2.9?

Using php 7.4.1 and MySQL 5.6.25 (both will be updated)

Thanks,
Stefan