Is it an issue with PyYAML
diff --git a/tools/requirements.txt b/tools/requirements.txt
index 97d0c7b..37264d3 100644
--- a/tools/requirements.txt
+++ b/tools/requirements.txt
@@ -1,6 +1,6 @@
# Items in this file must have a licence compatible with AL 2.0
-PyYAML~=6.0.1 ; python_version > "3.7" # MIT
-PyYAML~=5.4.1 ; python_version < "3.8" # MIT
+PyYAML~=6.0.1 ; python_version > "3.8" # MIT
+PyYAML~=5.4.1 ; python_version < "3.9" # MIT
# elasticsearch-dsl>=7.0.0,<8.0.0 # AL2.0 - not used by tools currently
# N.B. ES 7.14 introduces strict server version compatibility checks
elasticsearch[async]>=7.13.1,<7.14.0 # AL2.0