diff --git a/History.md b/History.md
index c30ecc3..97c8866 100644
--- a/History.md
+++ b/History.md
@@ -1,5 +1,10 @@
 # Liquid Change Log
 
+## 5.0.2 (unreleased)
+
+### Fixes
+* Fix support for using a String subclass for the liquid source (#1421) [Dylan Thacker-Smith]
+
 ## 5.0.1 / 2021-03-24
 
 ### Fixes
diff --git a/lib/liquid/version.rb b/lib/liquid/version.rb
index 47e3af7..724bca4 100644
--- a/lib/liquid/version.rb
+++ b/lib/liquid/version.rb
@@ -2,5 +2,5 @@
 # frozen_string_literal: true
 
 module Liquid
-  VERSION = "5.0.1"
+  VERSION = "5.0.2.alpha"
 end