The official Turner Classic Movies website has confirmed that there will be at least five more Scooby DTV movies released throughout the next three years. The movies will be Scooby-Doo Wrestlemania Mystery 2 in 2016, Scooby-Doo! Wild West in 2017 (along with another untitled 2017 DTV), and two untitled DTVs in 2018. Only one new movie has been confirmed so far for this year, meaning that this could be the first year since 2011 that we only see one Scooby movie released.
Thanks to mattpricetime on ScoobyAddicts for finding this.