diff --git a/rsshub/extensions.py b/rsshub/extensions.py
index 2ce9714..12210a9 100644
--- a/rsshub/extensions.py
+++ b/rsshub/extensions.py
@@ -1,8 +1,8 @@
-from flask_bootstrap import Bootstrap
+from flask_bootstrap import Bootstrap4
 from flask_debugtoolbar import DebugToolbarExtension
 from flask_moment import Moment
 
 
-bootstrap = Bootstrap()
+bootstrap = Bootstrap4()
 debugtoolbar = DebugToolbarExtension()
 moment = Moment()