diff --git a/requirements.txt b/requirements.txt
index 8d40de32c..246cc8fe0 100644
--- a/requirements.txt
+++ b/requirements.txt
@@ -8,7 +8,8 @@
 #
 ###############################################################################
 
-Flask==3.0.*
+Flask==3.0.*; python_version <= '3.8'
+Flask==3.1.*; python_version >= '3.9'
 Flask-Login==0.*
 Flask-Mail==0.*
 Flask-Migrate==4.*