Mention about the renaming of v4_beta branch in README
The [master](https://github.com/aws/aws-iot-device-sdk-embedded-C/tree/master) branch hosts the continuous development of the AWS IoT Embedded C SDK libraries. Please be aware that the libraries in master branch may have bugs and performance issues. Consider using the released versions of the AWS IoT Embedded C SDK for production ready software.
### v4_beta_deprecated branch
-The [v4_beta_deprecated](https://github.com/aws/aws-iot-device-sdk-embedded-C/tree/v4_beta_deprecated) branch contains a beta version of the AWS IoT Embedded C SDK libraries, which is now deprecated. The libraries in this branch will not be released. However, critical bugs will be fixed and tested. No new features will be added to this branch.
+The [v4_beta_deprecated](https://github.com/aws/aws-iot-device-sdk-embedded-C/tree/v4_beta_deprecated) branch contains a beta version of the AWS IoT Embedded C SDK libraries, which is now deprecated. This branch was earlier named as *v4_beta*, and was renamed to *v4_beta_deprecated*. The libraries in this branch will not be released. However, critical bugs will be fixed and tested. No new features will be added to this branch.
## Releases
