diff --git a/requirements.txt b/requirements.txt
index 04941f30..34c990fa 100644
--- a/requirements.txt
+++ b/requirements.txt
@@ -5,7 +5,7 @@ Flask-Babel>=0.11.1,<3.1.0
 Flask-Login>=0.3.2,<0.6.3
 Flask-Principal>=0.3.2,<0.5.1
 backports_abc>=0.4
-Flask>=1.0.2,<2.2.0
+Flask>=1.0.2,<2.3.0
 iso-639>=0.4.5,<0.5.0
 PyPDF>=3.0.0,<3.3.0
 pytz>=2016.10