diff --git a/ipympl/backend_nbagg.py b/ipympl/backend_nbagg.py
index 4dd2b6d..8272554 100644
--- a/ipympl/backend_nbagg.py
+++ b/ipympl/backend_nbagg.py
@@ -386,7 +386,7 @@ def _ipython_display_(self, **kwargs):
 
 
 class FigureManager(FigureManagerWebAgg):
-    if matplotlib.__version__ < "3.6":
+    if matplotlib.__version_info__ < (3, 6):
         ToolbarCls = Toolbar
 
     def __init__(self, canvas, num):