It has to be a two step upgrade...
Upgrade to 7.0 or an intermediate - upgrade your authorizations to analysis authorizations and then upgrade to 7.4.
As I understand - 7.3 upwards supports only Analysis authorizations. Also there might be some other obsolete things like Infopackage groups etc.
7.4 - AFAIK - does not have a 3.5 query runtime - you would need to have all your queries converted to 7.0 format before upgrading.
I would think that an initial upgrade to 7.0 , test and stabililze . Convert if required and then upgrade to 7.4 would be a safer approach.