diff --git a/requirements.txt b/requirements.txt
index 0fe2f67e4..b0a91d842 100644
--- a/requirements.txt
+++ b/requirements.txt
@@ -16,7 +16,7 @@ pyramid_celery
 pyramid_mako
 pytz
 pywps
-pyyaml
+pyyaml>=4.2b4
 requests
 requests_file
 shapely