diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml
index 8298978..03e1fbb 100644
--- a/.github/workflows/ci.yml
+++ b/.github/workflows/ci.yml
@@ -17,6 +17,9 @@ jobs:
           - ubuntu-latest
           - macos-latest
           - windows-latest
+        python-version:
+          - "3.12"
+          - "3.x"
 
     steps:
       - name: Check out repository
@@ -25,7 +28,7 @@ jobs:
       - name: Set up Python
         uses: actions/setup-python@v6
         with:
-          python-version: "3.13"
+          python-version: ${{ matrix.python-version }}
           cache: "pip"
           cache-dependency-path: pyproject.toml
 
@@ -43,5 +46,4 @@ jobs:
         with:
           token: ${{ secrets.CODECOV_TOKEN }}
           files: ./coverage.xml
-        if: matrix.os == 'ubuntu-latest'
-      
\ No newline at end of file
+        if: matrix.os == 'ubuntu-latest' && matrix.python-version == '3.x'
diff --git a/pyproject.toml b/pyproject.toml
index 522d0e3..88b3da7 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -19,7 +19,7 @@ dependencies = [
   "python-libsbml",
   "ruamel.yaml",
 ]
-requires-python = ">=3.13"
+requires-python = ">=3.12"
 description = "Specify parameter estimation problems and hybrid models."
 readme = "README.md"
 license = {file = "LICENSE"}