diff --git a/docs/Project.toml b/docs/Project.toml
index 6de778f..3e66f10 100644
--- a/docs/Project.toml
+++ b/docs/Project.toml
@@ -12,7 +12,7 @@ QuadGK = "1fd47b50-473d-5c70-9696-f719f8f3bcdc"
 SpecialFunctions = "276daf66-3868-5448-9aa4-cd146d93841b"
 
 [compat]
-AbstractTrees = "0.3"
+AbstractTrees = "0.3, 0.4"
 DifferentialEquations = "6.15, 7"
 Documenter = "0.27"
 GR = "0.46, 0.72"