diff --git a/pyproject.toml b/pyproject.toml
index 3ef7bdeb..23646146 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -37,8 +37,8 @@ nestpy = ">=2.0.2"
 numba = ">=0.58.1"
 awkward = ">=2.5.1"
 uproot = ">=5.2.1"
-strax = ">=1.6.0"
-straxen = ">=2.2.3"
+strax = ">=1.6.0,<2.0.0"
+straxen = ">=2.2.3,<3.0.0"
 utilix = ">=0.11.0"
 
 [build-system]