/guides/short-range-guides/b/mdk/posts/upgrading-to-a-new-mdk-release-in-keilIntroduction The Microcontroller Development Kit (MDK) provides basic device support such as register header files, startup files and errata workarounds. Every release of the nRF5 SDK contains the latest version of the MDK at the time of release, buten-USTelligent Community 13 Non-Production