README.md in rubocop-performance-1.8.1 vs README.md in rubocop-performance-1.9.0

@@ -74,9 +74,17 @@
 
 ## Documentation
 
 You can read a lot more about RuboCop Performance in its [official docs](https://docs.rubocop.org/rubocop-performance/).
 
+## Compatibility
+
+RuboCop Performance complies with the RuboCop core compatibility.
+
+See the [compatibility documentation](https://docs.rubocop.org/rubocop/compatibility.html) for further details.
+
+**Note:** Performance cops are all MRI focused and are highly dependent of the version of MRI you're using.
+
 ## Contributing
 
 Checkout the [contribution guidelines](CONTRIBUTING.md).
 
 ## License