diff --git a/lib/rom/mapper/version.rb b/lib/rom/mapper/version.rb
index 215e879..0f6524f 100644
--- a/lib/rom/mapper/version.rb
+++ b/lib/rom/mapper/version.rb
@@ -1,5 +1,5 @@
 module ROM
   class Mapper
-    VERSION = '0.5.0'.freeze
+    VERSION = '0.5.1'.freeze
   end
 end