Add disclaimer for community users

README.md

@@ -3,6 +3,9 @@
 [![Build Status](https://travis-ci.org/databricks/spark-redshift.svg?branch=master)](https://travis-ci.org/databricks/spark-redshift)
 [![codecov.io](http://codecov.io/github/databricks/spark-redshift/coverage.svg?branch=master)](http://codecov.io/github/databricks/spark-redshift?branch=master)
 
+## Disclaimer
+This is fork version from Databricks's spark-redshift repository. Our custom changes only tested with Spark **2.4.0** version. These custom changes may not be worked with older version of Spark
+
 ## Note
 
 To ensure the best experience for our customers, we have decided to inline this connector directly in Databricks Runtime. The latest version of Databricks Runtime (3.0+)  includes an advanced version of the RedShift connector for Spark that features both performance improvements (full query pushdown) as well as security improvements (automatic encryption). For more information, refer to the <a href="https://docs.databricks.com/spark/latest/data-sources/aws/amazon-redshift.html">Databricks documentation</a>. As a result, we will no longer be making releases separately from Databricks Runtime.