diff --git a/Project.toml b/Project.toml
index 2fd0a4b..99ecbae 100644
--- a/Project.toml
+++ b/Project.toml
@@ -31,6 +31,6 @@ Lazy = "0.13 - 0.15"
 MLStyle = "0.4"
 Memoize = "0.4"
 RegularizationTools = "0.4, 0.5"
-SpecialFunctions = "0.10, 1.0"
+SpecialFunctions = "0.10, 1.0, 2"
 Underscores = "2.0, 3"
 julia = "1"