diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml
index b4a1274..071c7fd 100644
--- a/.github/workflows/ci.yml
+++ b/.github/workflows/ci.yml
@@ -8,7 +8,7 @@ jobs:
     runs-on: ubuntu-latest
     strategy:
       matrix:
-        python-version: ["3.10"]
+        python-version: ["3.9"]
 
     steps:
       - uses: actions/checkout@v3
diff --git a/setup.py b/setup.py
index 16c4193..bfdfa90 100644
--- a/setup.py
+++ b/setup.py
@@ -19,7 +19,7 @@
     long_description=README,
     keywords=['metaheuristics', 'hyper-heuristic', 'optimization', 'automatic design', 'global optimization',
               'evolutionary computation', 'bio-inspired', 'algorithm design'],
-    python_requires=">=3.10",
+    python_requires=">=3.9",
     install_requires=(pathlib.Path(__file__).parent / 'requirements.txt').read_text(encoding='utf-8').split('\n'),
     extras_require={
         "ML": [