Last night was Apple’s third quarter earnings call and Tim Cook company’s third-quarter earnings call says that over four million people are running the beta versions of all four operating systems combined.

Unfortunately, Tim didn’t break down the numbers on an individual software basis, however it’s safe to assume that iOS makes up the majority of those four million beta users.

Cook said “In June, we hosted an extremely successful developers conference that previewed many major advances coming this fall to our four operating systems, iOS, macOS, watchOS and tvOS. Customer and developer reaction has been very positive, and we have over four million users participating in our new OS beta programs.”

Having over four million people running beta releases is certainly an impressive figure and is a good way of finding bugs for Apple.