Class isn't just suspended, it's been cancelled by the BBC. The Doctor Who spin off failed to get an audience, which is a shame given how rich and varied the show's universe is. Even a guest appearance from departing Doctor Peter Capaldi couldn't save it, so it looks like Whovians only have the main show to enjoy.
The show was already on hot water when Patrick Ness, the show's creator, announced that he would not be involved in the show's creative output in June. In hindsight, this could be seen as the writing on the wall for it's future, but it didn't seem that way at the time. Considering how popular Doctor Who is around the world, it's cancellation is a big disappointment.
BBC Three controller Damian Kavanagh said the following to Radio Times:
"I thought Patrick did a great job, he explored an amazing world. In honesty it didn't really land for us on BBC3; some shows don't and I have to make decisions about what we're going to do from a drama point of view, and what we did after Class was Clique which worked really well for us."
Fans will probably lament the fact that the cast of Class won't be able to interact with new Doctor Jodi Whittaker. While the show might not have been great, a second season could have explored the show's universe more, but it isn't meant to be. If any other spin offs are made, they will have to learn from the mistakes of Class.