diff --git a/s3.config.yaml b/s3.config.yaml
index 5eb69c6..00a50cc 100644
--- a/s3.config.yaml
+++ b/s3.config.yaml
@@ -29,7 +29,7 @@ s3_custom_resources:
     S3BucketCreateOnlyCR:
       code: s3_bucket.py
       handler: s3_bucket.handler
-      runtime: python3.7
+      runtime: python3.8
       timeout: 5
       role: S3CustomResource
       environment:
diff --git a/spec/cors_spec.rb b/spec/cors_spec.rb
index 7a5b6f2..22abaa5 100644
--- a/spec/cors_spec.rb
+++ b/spec/cors_spec.rb
@@ -109,7 +109,7 @@
       end
       
       it "to have property Runtime" do
-          expect(resource["Properties"]["Runtime"]).to eq("python3.7")
+          expect(resource["Properties"]["Runtime"]).to eq("python3.8")
       end
       
       it "to have property Timeout" do