diff --git a/pyproject.toml b/pyproject.toml
index 262f4094..25743ddc 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -92,7 +92,7 @@ tidy3d = [
 ]
 vlsir = [
   "vlsir>=4.0.0,<5.0.0",
-  "vlsirtools>=4.0.0,<5.0.0"
+  "vlsirtools>=4.0.0,<6.0.0"
 ]
 web = [
   "jinja2",