diff --git a/Project.toml b/Project.toml
index 6dafa90..f4b5119 100644
--- a/Project.toml
+++ b/Project.toml
@@ -40,6 +40,7 @@ JSON = "0.21"
 JSONSchema = "0.3"
 JuMP = "0.21"
 MathOptInterface = "0.9"
+OrderedCollections = "1.4"
 PackageCompiler = "1"
 ProgressBars = "0.6"
 Shapefile = "0.7"