Anyone know when...

I think it's current, but the producers did intend to have elements of cartoons from the 1990s blended in with the show:

"Skyler wanted to make a show that felt more naturalistic in tone, something that evoked the cartoons we grew up with in the '90s combined with a more modern sensibility," says Clarence writer Spencer Rothbell. "It's all about empowering kids and having fun."

Within this intended element of realism, the show makes plenty of references to popular culture. "We try to work in nods to movies and TV that have either inspired us or that fit the genre of that particular episode," Rothbell says.