diff --git a/Project.toml b/Project.toml
index d8aaa1358..e1a936e0a 100644
--- a/Project.toml
+++ b/Project.toml
@@ -11,7 +11,7 @@ Polynomials = "f27b6e38-b328-58d1-80ce-0feddd5e7a45"
 Reexport = "189a3867-3050-52da-a836-e630ba90ab69"
 
 [compat]
-Compat = "2.2, 3.0"
+Compat = "2.2, 3.0, 4"
 DiffEqBase = "6.5"
 Polynomials = "1.2, 2.0"
 Reexport = "0.2, 1"