diff --git a/setup.py b/setup.py
index 89c9b458..0853fbbf 100755
--- a/setup.py
+++ b/setup.py
@@ -57,7 +57,7 @@ def read(*names, **kwargs):
         # Fix upper version limits for pyomo and pandas
         # Related to problems with old pypsa version
         "pandas < 2",
-        "pyomo == 6.4.1",
+        "pyomo>6.4, <6.6",
         "pypsa == 0.20.1",
         "rtree",
         "saio",