diff --git a/releases/1.4.0/index.md b/releases/1.4.0/index.md
index 81845c6f..7057a408 100644
--- a/releases/1.4.0/index.md
+++ b/releases/1.4.0/index.md
@@ -32,5 +32,7 @@ custom_css: releases
 
 *(These are bugs found within the preexisting ontology that have been fixed.)*
 
+* Removed `owl:onDatatype` from vocabulary definitions ([*UCO GitHub Issue 593*](https://github.com/ucoProject/UCO/issues/593))
+
 
 ## Documentation