Codeforces supports a wide range of languages. Just yesterday I supported Java 11.
On the other hand, my website is not only just open public rounds and trainings, but also an advanced system of groups, custom domains and mashups. This ecosystem makes it possible to conduct private trainings, local contests/olympiads, provides the work of computer science clubs, and so on.
Sometimes you ask me to somehow limit the languages that can be used in a particular contest. For example, an official competition is held that does not support Rust. Or this contest is a practical session specifically for classes in Python.
Now you can configure allowed programming languages (more precisely, their groups) for your mashups and private trainings. Thanks for the help to geranazavr555 who helped to realize this opportunity!
Here are some screenshots of how it looks in action.
Edit a contest settings to specify the list of allowed languages.
You can choose program languages groups your contest supports.
Hope you enjoy the feature,