mettelus
I have been so caught up in things I have not even opened the new Z3TA yet. Does it have a VST2 version as well? I am wondering if disabling the "VST3 migration" in SONAR preferences would allow for older projects to be loaded with the VST2 version (i.e., SONAR wouldn't "swap it out," but use the newer version), but grasping at straws here.

I think this has been tried, without success.
 
Since there are new features, e.g. Mod Matrix Additions, this would result in changes to patch/program data saved in and read from fxp or application files. Something probably changed in the newer version that wasn't compatible with the old saved data. This is probably internal to Z3TA+ so not affected by the interface version (VST2/3).
 

I do go back to previous sessions, because I am still working on my album, still mastering, still mixing, etc.  

CWBRN-41790 - Now under investigation...

CWBRN-41790 - Submitted to development...

Was hoping to avoid an uninstall...  Any news on this one?

Not yet, unfortunately. 

You guys have been extremely patient, and I feel bad about not getting anything to you. We have a tentative fix for this issue that works in every DAW but Cubase, but we wanted to spend time with it and make sure things really work before sending it to the public [this time]. 
 
The problem was on our end; we merged the vst2 and vst3 codebases into one without making sure their IDs matched up, which made migration from vst2 to vst3 very difficult. Obviously we should have caught this sooner, so I apologize. 
 
I was hoping that you guys would get an update by the end of this week, but it doesn't seem like that's happening, so please try and bear with us, the fix is coming. 
 
By the way, if you're really blocked, I guess a crappy workaround would be to save any project instances you have as presets in 2.1, and then load them up again in 2.2. Of course this requires an uninstall.... and then a reinstall...but the issue only effects settings coming from a saved project (where the project had an instance of Z3TA+ 2.1, on Windows.)

Awesome. I'm a patient person.  I just appreciate that it's been addressed.  This is why I love Cakewalk. 

John Joseph [Cakewalk]
I was hoping that you guys would get an update by the end of this week, but it doesn't seem like that's happening, so please try and bear with us, the fix is coming. 

 
While I'm quick to complain, I'm also constantly impressed by the degree of communication and frankness Cakewalk blesses us with.  It can be a bit confusing at times !
 
I was pleased to see z3ta+2.2.2 magically appear at the top of my list of products as of today or yesterday.  Looking forward to playing with it, but I'll wait patiently for the update.
 

John thanks. Please keep up the excellent transparent communication.

Of course it's better for us to wait then get a half baked patch. Thanks be being straight up.