The evaluation should work in Unity 2019.2. It's compiled with API calls specific to 2019.2+. But it's also compiled with editor code specific to 2019.3's new editor UI, so it's possible you might see some superficial quirks in the Dialogue Editor, particularly in the conversation node editor. But it's nothing that should get in the way of everything running properly at runtime.
Great to hear it should keep working. I really like the way it works and how to use it. Seriously considering purchasing the paid version. If I do, will it be a simple update to my existing project with hopefully no errors. Or will I need to start the project over?
I'm glad to hear you're enjoying Quest Machine. Anything you make in the evaluation version is 100% compatible with the paid version. You won't have to do anything special. (Quick note on 2D projects: The evaluation version is precompiled with 2D Physics support enabled. When you switch to the paid version, you'll need to select Tools > Pixel Crushers > Misc > Enable 2D Support to enable it.)
BTW, if you already own a license for the Dialogue System, you'll get a 50% discount on Quest Machine. So if you're considering getting both, get the Dialogue System first as a separate purchase. Then get Quest Machine.
I will definitely check out your Dialogue System. It might be more than what I need for my current project, but purchasing it with a 50% discount for Quest Machine might just be a starter buy. I'm sure it work for future games. Thanks for offering it.
Is there anything to be aware of within Dialogue System and the use of Invector. Your tutorial dealing with Invector within Quest Machine was great.