diff --git a/Project.toml b/Project.toml
index 5f96605a..788dabcd 100644
--- a/Project.toml
+++ b/Project.toml
@@ -27,7 +27,7 @@ JSON = "0.20, 0.21"
 MacroTools = "0.5"
 Parameters = "0.12"
 ReverseDiff = "1.4, 1.5"
-SpecialFunctions = "0.8, 0.9, 0.10, 1"
+SpecialFunctions = "0.8, 0.9, 0.10, 1, 2"
 julia = "1.3"
 
 [extras]