Merge pull request #3660 from ARMmbed/release-candidate

Release candidate for mbed-os-5.3.4

Author: 0xc0170

README.md

@@ -11,9 +11,9 @@ The current release, along with a selection of previous versions are detailed he
 
 ## Getting Started for Developers
 
-We have a getting started guide for developers using mbed OS in applications:
+Please note that you will require [mbed CLI](https://github.com/ARMmbed/mbed-cli) to build mbed OS. For more details, please read the getting started guide for developers using mbed OS in applications:
 
-- [Getting Started](https://docs.mbed.com/docs/mbed-os-handbook/en/5.2/)
+- [Getting Started](https://docs.mbed.com/docs/mbed-os-handbook/en/latest/)
 
 ## Getting Started for Contributors