In the past I've installed Abella from git, but I thought I'd try it using opam. I am using Ubuntu 20.04. It tried to install 2.0.2 instead:
twilson-desktop:~$ opam install abella
The following actions will be performed:
∗ install ocamlbuild 0.14.0 [required by abella]
∗ install conf-m4 1 [required by ocamlfind]
∗ install ocamlfind 1.8.1 [required by abella]
∗ install abella 2.0.2
===== ∗ 4 =====
Do you want to continue? [Y/n] n
twilson-desktop:~$ opam --version
2.0.5
twilson-desktop:~$ ocaml --version
The OCaml toplevel, version 4.08.1
Any idea what the problem is?