diff --git a/Project.toml b/Project.toml
index 28c2e12e..9edbab0b 100644
--- a/Project.toml
+++ b/Project.toml
@@ -74,7 +74,7 @@ Missings = "0.4"
 ModelConstructors = "^0.2.4"
 Nullables = "^0.0.8, 1"
 Optim = "0.16, 0.17, 0.18, 0.19, 0.20, 0.21, 0.22, ^1.2.1"
-OrderedCollections = "~1.1, ~1.2, =1.3.1, =1.3.2"
+OrderedCollections = "~1.1, ~1.2, =1.3.1, =1.3.2, 1.6"
 PackageCompiler = "^0.6.4, 1.0, 1.1, 1.2"
 Plots = "0.19, 0.20, 0.22, 0.23, 0.24, 0.25, 0.26, 0.27, 0.28, ~1.1, ~1.2, ~1.3, ~1.4, ~1.5, ~1.6, ~1.7, ~1.8, ~1.9, ~1.10, 1.14, 1.15"
 RecipesBase = "0.5, 0.7, 0.8, 1.0"