There are two pages for upgrading to latest 3.3:
https://doc.ibexa.co/en/latest/update_and_migration/from_2.5/to_3.3.latest/#b-v337
https://doc.ibexa.co/en/latest/update_and_migration/from_3.3/update_from_3.3/#v3324

The first url I refere to stops at v3.3.24, while the other goes on to 3.3.34. There are also variations on the steps up to 3.3.24 when comparing the two pages.

Also, this script is not mentioned in either of the pages : https://github.com/ibexa/installer/blob/v1.0.17/upgrade/db/mysql/ibexa-3.3.34-to-3.3.35.sql