diff --git a/requirements.txt b/requirements.txt
index 5140afdf0..775eecfc4 100644
--- a/requirements.txt
+++ b/requirements.txt
@@ -35,7 +35,8 @@ cryptography
 # use cwltool gpu-enabled support until integrated within the original tool
 # (https://github.com/common-workflow-language/common-workflow-language/issues/587)
 ### git+https://github.com/crim-ca/cwltool@docker-gpu#egg=cwltool; python_version >= "3"
-cwltool==3.1.20230213100550
+cwltool==3.1.20230719185429; python_version <= "3.6"  # pyup: ignore
+cwltool==3.1.20230906142556; python_version >= "3.7"
 docker
 duration
 esgf-compute-api @ git+https://github.com/ESGF/esgf-compute-api.git@v2.3.7