diff --git a/Project.toml b/Project.toml
index 63c4809..fc650f8 100644
--- a/Project.toml
+++ b/Project.toml
@@ -36,7 +36,7 @@ LatinHypercubeSampling = "1.9.0"
 LineSearches = "7"
 LinearAlgebra = "1"
 NonlinearSolve = "4.8.0"
-Optim = "1"
+Optim = "1, 2"
 Polyester = "0.7"
 Printf = "1.9 - 1.12"
 Random = "1"