diff --git a/Project.toml b/Project.toml
index 69461b7c4..fad87b534 100644
--- a/Project.toml
+++ b/Project.toml
@@ -135,7 +135,7 @@ Measurements = "2"
 NamedArrays = "0.9, 0.10"
 NestedSamplers = "0.8"
 Optim = "0.19,0.20, 0.21, 0.22, 1"
-Optimization = "3"
+Optimization = "3, 4"
 PDMats = "0.9, 0.10, 0.11"
 ParallelProcessingTools = "0.4"
 Parameters = "0.12, 0.13"