I'm currently fucking around with transitioning existing production #Helm releases from how they were on pre-2.7 Rancher to post-2.7 #Rancher.

Really annoying, because Rancher just deprecated it, making this a huge breaking change, but they didn't provide a fix for existing deployments. You basically have to purge the old release (not a good idea in a lot of production scenarios) or fiddle with this old release, punch & grab it by the Gopher, until it finally starts working, as it should again, i. e. being in the new Apps section, rather than in the Legacy section...