There are no updates, and as far as I am aware it will run on any Mac with any OS X version, at least since 10.2.On Tiger and Leopard it displays magenta triangles on the map, which is annoying, but doesn't stop it working.
It's a bit fussy about the config you run it in. It will only run when placed in a Civ3 vanilla folder where the Civ3 .bic file is from version 1.21g, and it must not be in a subfolder.