diff --git a/Project.toml b/Project.toml
index 1fd166d..7fb0183 100644
--- a/Project.toml
+++ b/Project.toml
@@ -8,6 +8,7 @@ NaNMath = "77ba4419-2d1f-58cd-9bb1-8ffee604a2e3"
 SpecialFunctions = "276daf66-3868-5448-9aa4-cd146d93841b"
 
 [compat]
+Calculus = "0.5"
 NaNMath = "0.3"
 SpecialFunctions = "0.7, 0.8, 0.9, 0.10, 1.0"
 julia = "0.7, 1.0"