What is the maximum number of students in a group class?

We have restricted the number of students in a group class to 10, which we find to be an optimal number. Tools such as breakout rooms provide the opportunity for pair work or small group work, where all participants have more of an opportunity to practice speaking, the same in a physical classroom. We are aware that students might need some time for adaptation to virtual classes if they did only Face-to-Face classes before. We are confident that the group size is suitable for the medium.