diff --git a/test/downstream/Project.toml b/test/downstream/Project.toml
index 5740bc9a7..701614642 100644
--- a/test/downstream/Project.toml
+++ b/test/downstream/Project.toml
@@ -38,6 +38,7 @@ ModelingToolkitStandardLibrary = "2.7"
 NonlinearSolve = "2, 3, 4"
 Optimization = "4"
 OrdinaryDiffEq = "6.33"
+PartialFunctions = "1"
 Plots = "1.40"
 RecursiveArrayTools = "3"
 SciMLBase = "2"