There are a lot of questions asked with the “Canasta” tag where the answer depends on whether they are playing Classic Canasta or Modern Canasta. There are a handful of rules that overlap between the two; but not as many as there are rules where they are different.
I think most questions asked about Canasta are talking about Classic Canasta; as that seems to be the more popular version (some websites that list the rules for it only refer to it as “Canasta”).
Alternatively the Canasta tag could stay the same, with a new tag added for Modern American Canasta.