Yes, that was the good news and the not so good news is, that Sanjay Dutt and Arshad Warsi will be uniting for the next film of Housefull 4 director Farhad Samji and not for the next film of Munna Bhai film series.
According to a newspaper, Sanjay Dutt will play the role of a blind don in this one and Arshad Warsi will be his partner who will be his eyes. The fun fact is that no one in the film is aware that Sanjay's character is blind and Arshad's character can't reveal that to anyone. Arshad Warsi also told that the script of the film is an amazing one.
Arshad also said that the shooting of this film will commence between February - March next year, which indicates that it should be released by the end of next year. It is notable that the duo of Sanjay Dutt and Arshad Warsi have appeared in the 'Dhamaal' film too, franchise apart from the Munnabhai film series.