diff --git a/src/ReinforcementLearningExperiments/Project.toml b/src/ReinforcementLearningExperiments/Project.toml
index 57c9852be..92c728ee9 100644
--- a/src/ReinforcementLearningExperiments/Project.toml
+++ b/src/ReinforcementLearningExperiments/Project.toml
@@ -32,7 +32,7 @@ Weave = "44d3d7a6-8a23-5bf8-98c5-b353f8df5ec9"
 Zygote = "e88e6eb3-aa80-5325-afca-941959d7151f"
 
 [compat]
-AbstractTrees = "0.3"
+AbstractTrees = "0.3, 0.4"
 ArcadeLearningEnvironment = "0.2"
 BSON = "0.3"
 CUDA = "3"