Happy to be of help. OJS 2.3.4 is basically a stability/bugfix update of OJS 2.3.3, and so doesn't include any new functionality -- just fixes. (You may want to see the OJS Recommended Patches
page; the 2.3.3.-3 subpage lists all bug fixes that OJS 2.3.4 includes.)This page
includes a partial listing of changes between OJS 2.2.x and 2.3 -- it's the highlights, basically. You should be able to combine that and the OJS 2.3.3 "What's New
" page to get a good idea on the new functionality that editors will see once you've upgraded.
From 2.3.3 on, we'll be releasing a new userguide every time we release a major (feature-changing) release of the software; and we'll package a "what's new" page along with the guide, so that all necessary information is available in one place.
If you have any further questions about the changes you see, let us know!