diff --git a/Project.toml b/Project.toml
index 91c0cf2..0990d00 100644
--- a/Project.toml
+++ b/Project.toml
@@ -26,7 +26,7 @@ XGBoostTermExt = "Term"
 
 [compat]
 AbstractTrees = "0.4"
-CEnum = "0.4"
+CEnum = "0.4, 0.5"
 CUDA = "3, 4, 5"
 JSON3 = "1"
 OrderedCollections = "1"