diff --git a/Project.toml b/Project.toml
index b564a30..7602118 100644
--- a/Project.toml
+++ b/Project.toml
@@ -21,6 +21,6 @@ CSV = "0.4, 0.5, 0.6, 0.7, 0.8, 0.9"
 DataFrames = "0.13, 0.14, 0.15, 0.16, 0.17, 0.18, 0.19, 0.20, 0.21, 0.22, 1.0"
 NLopt = "0.5.1, 0.6"
 PhyloNetworks = "0.11, 0.12, 0.13, 0.14"
-SpecialFunctions = "0.8, 0.9, 0.10, 1.0"
+SpecialFunctions = "0.8, 0.9, 0.10, 1.0, 2"
 StatsFuns = "0.7, 0.8, 0.9"
 julia = "1.2, 1.3, 1.4, 1.5, 1.6"