diff --git a/Project.toml b/Project.toml
index 94223267..86cc036e 100644
--- a/Project.toml
+++ b/Project.toml
@@ -81,6 +81,6 @@ SparsityDetection = "0.1"
 StaticArrays = "0.10, 0.11, 0.12"
 StatsPlots = "0.12"
 Sundials = "3.8"
-Unitful = "0.17"
+Unitful = "0.17, 0.18"
 Weave = "0.9"
 julia = "1"