Upgrade to a new plugin version? Or to a new engine version? I would suggest keeping the template as a separate project entirely that you can pull blueprints and objects from to use outside of it. Kind of like the “content packages” that ue4 has except not automated. I will be adding thing to it often enough that trying to keep something working and get the updates at the same time would likely slow you down more than help you.
For engine versions, it should currently just upgrade, I have been trying to support the current / preview versions as it goes and when the preview goes live support the older version until the next preview if possible. 4.12 was an exception as the code base changes from it to 4.13 were too dramatic. I anticipate the plugin in its updated state losing 4.13 support and locking a branch for it when 4.15 comes out, the enum changes coming down the pipeline are not compatible.
**Also, to anyone else: (going to post in the OP as well)
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I would like to note by the way that everything currently in the template is an example of what I think is best practices (though still needing a little polish as I made it over three days), not everyone is going to need the same set up and not everyone is going to need a full VRcharacter. Custom pawns that just use the motion controllers and camera / parent relative component would be useful to people that don’t want gravity / collision. The entire plugin itself isn’t so much a complete package as one (or for the character/grips, several) example(s) of how to achieve VR capabilities in UE4…like a big public research endeavor on my part. Some things I know I would have done slightly differently if I were to go back and start over (gripping code out of the motion controllers and into a custom component that has its own late update referencing the controllers for example).
I have not changed some things that I know could be slightly better if refactored as there are projects released on steam already that use it and I don’t want to break compatibility beyond repair for them.
The new SimpleVRCharacter is a more sane method of creating a VR colliding character, when I made the original one I wanted every possible feature I could think of and I broke a bunch of “soft rules” to make it happen. The new one does none of that, so while slightly less feature complete it is more in line with standard procedure for the engine.