The issue is that we are constantly adding new PHP versions because the security ecosystem itself requires us to do so. In practice, this means adding the new versions to additional slots.
If you want an old version to persist then you could add it to an higher slot number and keep it there.
But I know what you mean. Kindlike how CP has it. You can choose there that a PHP version will be inherited or not. If not, then it will automatically kept if the main server PHP version will change, provided that the choice for multiple PHP options is present.
Like
@zEitEr explained DA does not have such inherited on/off function but another config method.
You could suggest such feature request in the
Directadmin Feedback site (click). You need a seperate login for that.
Personally I always look with the php versions list (extended) plugin which users have which php version.
Then I implement the new php version and at the same time set the older php version to option 2.
After completing I move all users which have php version 1 to php version 2 and then afterwards they can select to change it to the newer version themselves and things keep working.
You might want to check
this thread (click) for it, but there are more. Or write a script for it as already suggested.
Personally we always put a new php version as last for example option 4. Then users can test for a couple of weeks and upgrade their stuff. After that we set it to option 1 and put all or most users to it, except the few who do not have option 4 then, they need to be moved seperately.
It's a bit of work, but it's 1 method. Most likely there are others, maybe better methods.