diff --git a/Project.toml b/Project.toml
index a8ea16a25..d7c0809fe 100644
--- a/Project.toml
+++ b/Project.toml
@@ -33,7 +33,7 @@ IRTools = "0.4"
 MacroTools = "0.5"
 NaNMath = "0.3"
 Requires = "1.1"
-SpecialFunctions = "1.6"
+SpecialFunctions = "1.6, 2"
 StatsFuns = "0.9.8"
 ZygoteRules = "0.2.1"
 julia = "1.3"