diff --git a/gradle.properties b/gradle.properties
index 3e15dbe..2c0ac8c 100644
--- a/gradle.properties
+++ b/gradle.properties
@@ -4,4 +4,4 @@ version=1.0.9-SNAPSHOT
 dokkaVersion=0.9.14
 hamkrestVersion=1.4.2.0
 junitVersion=4.12
-kotlinVersion=1.2.21
+kotlinVersion=1.2.40