Parallels Desktop 12 Update, but can`t find old key...

As written in the title, after upgrading to new OS X, I bought a Parallels Upgrade, since I already bought the full version a few years ago.
Asked for the key, I don´t remember where I put the box...
In my account I can only find information about the new Upgrade I just bought and nothing older than that...
Can you please help me?
Thanks,
Sophie

 

Can somebody help me? It´s very very urgent, since I need Parallels for my job!
Thanks a lot,
Sophie

 

Please check the blog to locate your Parallels Desktop activation key.