diff --git a/.github/workflows/set-up-environment.yml b/.github/workflows/set-up-environment.yml
index 18dc6ae..c5f3c5f 100644
--- a/.github/workflows/set-up-environment.yml
+++ b/.github/workflows/set-up-environment.yml
@@ -19,14 +19,14 @@ jobs:
       run: |
         opam update
         opam install why3.1.6.0
+        # install both alt-ergo 2.4.2 and alt-ergo 2.5.3
         opam install alt-ergo.2.4.2
         eval $(opam env)
         cp $(which alt-ergo) $(which alt-ergo)-2.4.2
         opam install alt-ergo.2.5.3
         eval $(opam env)
-        opam install eprover.2.6
-        # it's possible to install z3 as follows
-        # opam install z3.4.11.2
+        cp $(which alt-ergo) $(which alt-ergo)-2.5.3
+        opam install eprover.3.0
     - name: download z3, cvc4, and cvc5
       run: |
         mkdir downloads