Yeah, the change to 4.4.1 isn’t a change, just clarifying what was already the case elsewhere in the manual.
The big change here is that they’ve clarified the Layout and Marking diagram significantly. They added a new sheet (page 4) giving reference dimensions of the Shield Generator corners from the center of the field, which I know people have been looking for. Even more importantly, the diagrams used to say (and have for the last several years, if I recall correctly) that dimensions had a tolerance of 0.01 inches, which was… err… not really possible. It now specifically calls out the tolerances to be ±½″, which is much closer to being realistic. In practice, by the end of the weekend sometimes the fields are several inches longer, with odd bunches in the carpet, just from robots bashing into everything all the time, so I’m not sure one can really hold a field to it throughout an event. But now it’s certainly at least a standard one can try to expect for the start of an event. (And the opening to manual Chapter 3 ARENA even calls them “assembly tolerances”, not “throughout event tolerances”.)