diff --git a/tests/requirements.txt b/tests/requirements.txt
index 06c559b64..e5ec9c7e7 100644
--- a/tests/requirements.txt
+++ b/tests/requirements.txt
@@ -12,7 +12,7 @@ Pillow>=8.1.2,<9.0
 # Use pre-compiled wheel from packagecloud
 dlib==19.24.2.post1
 flask-cors>=3.0.9,<4.0.0
-flask>=1.1.2,<2.0.0
+flask>=1.1.2,<4.0.0
 gpiozero>=1.6.2,<2.0.0
 imutils>=0.5.4,<1.0.0
 isc_dhcp_leases>=0.9.1,<1.0.0