Google Translation:

Notice on the prohibition of QB series

We recently discovered that QB4.x series has data reporting errors

This problem has caused serious data statistics errors. In order to protect the rights and interests of users, TTG will immediately terminate support for qb 4.x. Users can choose to downgrade to qb 4.0 or lower or use other clients such as transmission.

The existence of such a situation has not yet been confirmed for QB 3.x. If similar situations occur, its support may be terminated at any time.
The management team will wait for the first stable version after a complete repair and add support.
Warning: If you insist on using the qb4.x version of the client, the resulting download statistics abnormality will be borne by you