I am not able find any related information regarding to my current situation. Is it possible to use the Oxygen 14.1 xml author with DITA-OT 2.5.2? We plan to upgrade our sofware too, but before that the leaders of my company are interested in the possible benefits of the new DITA-OT version.
You could try using the new OT with oXygen 14.1. I believe that you'd have to create versions of the transforms to point to the new OT. However, you won't be able to use any DITA 1.3 features unless you extend the oXygen framework to pick up the newer DTDs. Probably more work than using a trial version of 19.