Help files in Vanilla normally show when the object has been updated as well. In the case of adc~/dac~ it says it was last updated in 0.47, so if you don't know how to look for it on github, you can try a guess.
Make a feature request at the Purr Data repo.
Feels more like a 'bugfix' than a "feature request", please report it anyway nonetheless. But anyway, have the person use vanilla in the meantime this doesn't get fixed, there's no problem in having both installed ;)