Evaluation lab kit downloads & expirations

https://www.microsoft.com/en-us/evalcenter/evaluate-mem-evaluation-lab-kit

The MEM eval lab kit recently got updated with a new expiration of May 2, 2021.  However I had downloaded it at the beginning of February and its expiration date then was *really* close at Feb 7, 2021.  I have a few questions about its expiration.

First, what exactly happens when it expires?  It's now a few days past the previous Feb 7th expiration date and it still 'appears' to be working.  How long do I have?  What breaks and when?

Depending on the answers above, is there any migration/upgrade path to a newer lab kit from an older one?  Or anything salvageable from an older lab kit... like the client VMs?

Is it possible I can rename all the older lab kit VMs within Hyper-V, install the new lab kit, and jump back and forth between the different lab kit versions?

thanks!

Scott