Yes, you can see this: http://otrs.github.io/doc/manual/admin/stable/en/html/upgrading.html
If you are running a lower version of OTRS you have to follow the upgrade path to 4 first (3.0->3.1->3.2->3.3->4)! You need to perform a full upgrade to every version in between, including database changes and the upgrading Perl script.
What I don't understand: Does the sentence "You need to perform a full upgrade to every version in between" only refer to the situation when you start from a version lower than 4 or also for start versions above 4? From 4.0.1 -> 5.0.9 do I have to go through 4.0.1->4.0.2->4.0.3->...->5.0.9 or can I jump directly 4.0.1->5.0.9? And if all intermediate steps are required: What do I use as 5.0: 5.0.0.rc1? I'm using RPM packages and there is no 5.0.0 package on ftp://ftp.otrs.org/pub/otrs/RPMS/rhel/6/. frank