diff --git a/CHANGELOG.md b/CHANGELOG.md
index 2f8b328..dc208a6 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -5,6 +5,7 @@ All notable changes to this project will be documented in this file. This change
 ### Fixed
 - Long and double arguments to upcalls failed to compile in some cases
 - Void return types on upcalls would crash on serialization
+- Non-primitive types on upcalls was unsupported and would generate invalid bytecode with `nil` instructions
 
 ## [0.1.251] - 2021-10-14
 ### Fixed