Hacker News Reader

Depending on your system, the properties of the app may have the version, without even opening the browser. I.e. ‘Get info’ in OSX, ‘Properties’ in Windows. Dunno about Linux, but in that case people are likely to use package managers instead anyway.

Hamburger (≡) → Help → About?

Same as regular Firefox, right? Help -> About, and it'll tell you if it's outdated.