diff --git a/build.gradle b/build.gradle
index 6cb048b..42ed768 100644
--- a/build.gradle
+++ b/build.gradle
@@ -1,5 +1,5 @@
 plugins {
-    id 'net.ltgt.apt' version '0.19' 
+    id 'net.ltgt.apt' version '0.21' 
 }
 group 'com.asteroid.duck'
 version = '0.0.1'