diff --git a/pyproject.toml b/pyproject.toml
index db2f468..a4da607 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -30,7 +30,7 @@ classifiers = [
 dependencies = [
   "ipywidgets>=8.0.0",
   "numpy<2.0.0",
-  "widget_code_input",
+  "widget_code_input<4.0.0",
   "matplotlib",
   "termcolor"
 ]