Info here: http://www.tvshowsondvd.com/news/Charles-Charge-Season-4/11223

Yeah well even if season 4 would be retail release I still would order online. As no stores near me was selling season 3. I ended up buying it online.
I buy all my TV shows online now. Got so sick and tired of running around looking for a DVD on date of release and to discover none of the stores in my area are not selling the DVD's that I want. Waist of gas and time.