So here's the story behind my previous statement.
Last night I opened LabVIEW 2021 (21.0.1f2) to investigate a problem someone was having with software we provide for machines we sell. For reasons I can't currently explain, I was presented with a dialog listing several VIs (19 I think) and the following message for each one:
OpenG Libraries support for LabVIEW 2021 is missing and is referenced by the following VIs
This is very strange because I know I updated the OpenG Libraries months ago (possibly nearly a year ago) and have never had this come up before. Once I opened my main VI, I found that it was broken, and drilling-down into the sub showed that multiple VIs were broken (including the GCraftsman JSON Object Serialization library I briefly used but never got back to.
I spent about 4 hours researching why this would happen. I found several references to the updates to the OpenG libraries, and some recommending downgrading the libraries to the previous versions (version 4.x and 5.x). I tried this, but ended up with different errors. Eventually I realized I hadn't yet restarted LabVIEW after the downgrade, so I chalk the new errors up to that. But after restarting, then downgrading and re-upgrading to version 6.x of OpenG, suddenly the problem is now resolved.
My frustration in the earlier comment was that this update was going to prevent me from using GCraftsman's library specifically, due to the fact that I can't find any recent info from the developer anymore. This led me to worry for other users of libraries that can't be fixed after such a change.
It appears this was a false alarm since my code now runs fine; I guess reinstalling the OpenG libraries did the trick, but I have no idea why this was needed. The recompile triggered after the update seems to be working as intended even if it didn't originally work at all for me? Anyway, sorry for the disruption.