Looks like MIT Scheme (on which the ScmUtils system runs) still gets some regular maintainence releases, though I don't know how active development is these days:

https://www.gnu.org/software/mit-scheme/ https://ftp.gnu.org/gnu/mit-scheme/stable.pkg/

Installation instructions for the ScmUtils package:

http://groups.csail.mit.edu/mac/users/gjs/6946/index.html

As far as I know, Gerry and Jack still teach the course every year (can someone currently at MIT verify?) and still use the system.