For eligible customers who activated and registered their product after August 1, 2020 and before September 30, 2020 upgrade keys will automatically be added to the Parallels account and you will receive an automatic upgrade notification via email.
You should receive your upgrade key automatically within 7 days after the new version of Parallels Desktop for Mac becomes available. The upgrade key will be sent to the email that was used for registration of your Parallels Desktop 15 for Mac license. Meanwhile, you can use a trial copy of Parallels Desktop 16.
If you have not yet registered your copy of Parallels Desktop 15 for Mac, please register it in your Parallels account.
For more information please visit: http://www.parallels.com/techguarantee2020/