diff --git a/Project.toml b/Project.toml
index 466c1d5..1d5553a 100644
--- a/Project.toml
+++ b/Project.toml
@@ -12,9 +12,9 @@ ReinforcementLearningEnvironments = "25e41dd2-4622-11e9-1641-f1adca772921"
 StatsBase = "2913bbd2-ae8a-5f71-8c99-4fb6c76f3a91"
 
 [compat]
-julia = "1"
 Flux = "0.11"
 ReinforcementLearningBase = "0.8.5"
 ReinforcementLearningCore = "0.5.1"
-ReinforcementLearningEnvironments = "0.3.3"
+ReinforcementLearningEnvironments = "0.3.3, 0.4"
 StatsBase = "0.33"
+julia = "1"