diff --git a/.github/workflows/build.yml b/.github/workflows/build.yml
index a8c68b2..38042b0 100644
--- a/.github/workflows/build.yml
+++ b/.github/workflows/build.yml
@@ -58,18 +58,36 @@ jobs:
     strategy:
       matrix:
         os: [ubuntu-latest, macos-13, macos-14]
-        ocaml: ["5.2.0"]
+        ocaml: ["5.2.0", "5.1.1"]
         include:
           - os: ubuntu-latest
             version: "1.19.0"
+            ocaml: "5.2.0"
             linking: static
             target_triple: x86_64-unknown-linux-musl
           - os: macos-13
             version: "1.19.0"
+            ocaml: "5.2.0"
             linking: dynamic
             target_triple: x86_64-apple-darwin
           - os: macos-14
             version: "1.19.0"
+            ocaml: "5.2.0"
+            linking: dynamic
+            target_triple: aarch64-apple-darwin
+          - os: ubuntu-latest
+            version: "1.18.0"
+            ocaml: "5.1.1"
+            linking: static
+            target_triple: x86_64-unknown-linux-musl
+          - os: macos-13
+            version: "1.18.0"
+            ocaml: "5.1.1"
+            linking: dynamic
+            target_triple: x86_64-apple-darwin
+          - os: macos-14
+            version: "1.18.0"
+            ocaml: "5.1.1"
             linking: dynamic
             target_triple: aarch64-apple-darwin