The  last update  was  in 2014  (9.2),  but a  major
release came out since (10.x).

See discussion at https://discourse.nixos.org/t/6776
but to sum up:

The portable  C source and Windows  binaries are not
available in the latest MIT Scheme release
(see https://www.gnu.org/software/mit-scheme/release.html )
Warning: Locale seems not configured
hence  the  option  to  build from  source has  been
removed  from  `default.nix`.  Although there  is  a
source package  included in the release  (in lieu of
the portable C source), there is a caveat:

> Note that you cannot build a working system from the
> source  unless you  have  a  working MIT/GNU  Scheme
> compiler to do the  compilation. (This doesn't apply
> to the  portable C source,  which requires only  a C
> compiler.)  This means  that if  the above  binaries
> don't work  on your system,  it is pointless  to try
> building a  custom set  of binaries from  the source
> code.

mit-scheme: 9.2 -> 10.1.10