opam upgrade but I am still using an old version of ocaml. Why?
What’s the output of
opam switch list, it’s likely you specified a precise version to use, and thus you can upgrade it from
opam switch ... as normal.
opam help switch for help.
You can also run
opam upgrade --unlock-base to upgrade all the packages of the current switch including the compiler.
(by default opam will not change the version of the compiler you are using; the
--unlock-base option tells it to lift that restriction)