Hi all, I've been on Lemmy for like a week so am clearly an expert.
To sum up: Lemmur is defunct, you want Jerboa for Android or Mlem for iOS. But on Android you can also install your home instance as an app to your home screen (in mobile Chrome, hit the three dots menu and "add to home screen" or "install app") and basically use the mobile website, which I have to be honest works a lot better than Jerboa in a lot of ways.
Jerboa's latest update (0.33, I think?) is a big improvement, it feels pretty good now. Not perfect yet, of course, but very nice progress in the last few days!