When you purchase a DMDE license, it is typically not a one-time purchase for life-long updates. Most professional data recovery tools use a subscription or "update period" model.
DMDE License Key Update Guide: How to Renew and Activate Your Software dmde licensekey upd
If you have already purchased an upgrade or renewal, follow these steps to apply your new credentials: When you purchase a DMDE license, it is
Online: Simply enter the code while connected to the internet. When you purchase a DMDE license
Extract the Software: DMDE is portable. Extract the ZIP file to a folder on your drive (preferably not the drive you are trying to recover data from). Run the Program: Launch dmde.exe.