diff --git a/pyproject.toml b/pyproject.toml
index 681588d..7133d84 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -16,7 +16,7 @@ classifiers = [
 dependencies = [
     "numpy",
     "scipy",
-    "xrt",
+    "xrt~=1.6.2",
     "websockets",
     "xraydb",
 ]