Do I upgrade to 1.6ST first like most post I have seen in the past or I can go from 1.6 RC4 directly to 1.10.4 as suggested here https://docs.osticket.com/en/latest/Getting%20Started/Upgrade%20and%20Migration.htmlFrom time to time it will be necessary to upgrade your osTicket installation to the latest version, either to fix bugs or gain new features. Starting with version 1.6, osTicket is a complete rewrite with new database schema and code base making it hard to simply upgrade from previous versions.
Only previous versions from version 1.6 RC1 can be upgraded to the current version.If your osTicket version is older than 1.6, you need to look into migration instead.