hi, short answer: sort of... i run the latest version of the main branch (https://github.com/MbinOrg/mbin). kbin.run is kind of my guinea pig when it comes to testing latest code changes that impact federation, so you'll more than likely see the latest changes that have been approved by the other maintainers once i get a chance to update the server. fedia is such a big instance that we recommended jerry stick to only tagged releases of the code.
and there is actually a way for instance admins to change the default theme (image attached), but i've left it stock in case people don't like the tokyo night theme (but it's my favorite). users can change it in the setting menu (gear icon) in the righthand panel.