I registered my VStudio in 2017, but have not used it on my current machine. I have now reinstalled it, but the serial number doesn't work anymore. I can also not request a new serial.
1) to get newer free serial, please go to our site, login into your account,
then in the shop choose FREE VStudio, you will get new serials in a few minutes.
2) The free edition of Valentina Studio allows to play a little with PRO features, usually with limit - no save changes to disk.
Details described on the below wiki page
Sometimes on request, we can provide 1-2 weeks time limited Pro serial for more deep learning.