diff --git a/requirements.txt b/requirements.txt
index 8128d94bbe..10b7e2ff74 100644
--- a/requirements.txt
+++ b/requirements.txt
@@ -28,7 +28,7 @@ pycups==2.0.4  # https://pypi.python.org/pypi/pycups
 PyPDF2>=1.26,<3.1  # https://github.com/mstamy2/PyPDF2/blob/master/CHANGELOG
 
 # Only for cmsPrometheusExporter
-prometheus-client>=0.7,<0.8  # https://pypi.org/project/prometheus-client
+prometheus-client>=0.7,<0.22  # https://pypi.org/project/prometheus-client
 
 # Only for cmsTelegramBot
 python-telegram-bot>=21.9,<21.10 # https://pypi.org/project/python-telegram-bot