During the clone rebellion on Kamino, the 501st secured Jango Fett's DNA template before finishing off the remaining renegade clones. That was about a decade before the rebellion's attack. So are there any sources regarding how long the Empire or its successors continued to use cloned Stormtroopers, and more specifically how long did they continue to use Jango Fett's template? Did the Empire or its successors eventually lose/destroyed it, or do they still possess it?
Star Wars: The Clone Wars implied that the template wouldn't last infinitely.
From the episode Clone Cadets:
Ever since the unfortunate death of Jango Fett, we have had to stretch his DNA to produce more clones...
...Sometimes our efforts are less than successful.
Star Wars: Rebels shows that the Empire no longer uses the clone troopers.
Without being explicably told what happened, we can probably assume that the template was corrupted beyond use and/or the Empire decided to retire it along with the clone program.