diff --git a/README.md b/README.md
index a1dfe8a..7a96d96 100644
--- a/README.md
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@@ -19,6 +19,7 @@ The `SubclassSelector` attribute allows you to easily set subclasses of those ab
 - **[New]** Restore values of previous object from JSON when subclass is changed. (required Unity 2021.3 or later)
 - **[New]** Copy & Paste the subclass properties. (required Unity 2021.3 or later)
 - **[New]** Clear & reset the subclass properties. (required Unity 2021.3 or later)
+- **[New]** Covariance / Contravariance support. (required Unity 2023.2 or later)
 
 > See below for the reason for the limitation of versions less than Unity 2021.3.
 >