diff --git a/History.markdown b/History.markdown
index d14bf940..65ba60de 100644
--- a/History.markdown
+++ b/History.markdown
@@ -8,6 +8,7 @@
 ### Bug Fixes
 
   * Use jekyll-feed to generate the default site's RSS feed (#5196)
+  * Site#configure_theme: do not set theme unless it's a string (#5189)
 
 ### Site Enhancements