I really isn't very complicated.
I've based all my templates on the index.php file, so its just to compare the old index file with the new one - and transfer any changes to the templates. From 3.4.2 to 3.4.4 that file has remained unchanged.
ONE OTHER QUESTION is how important it is to upgrade the theme. If it runs smoothly and no new (for me) crucial features are added, does it make any sense?
(Have tried to search a tread about this, but strangely enough haven't found any)