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, but what happens if a new errata is discovered or if you need support for a new SoC revision? You should then upgrade your projects to use a newer MDK release. This guide explains how to do so for Keil µVision 5.
For Keil µVision 5 you find the MDK in the Pack Installer, under the name nRF_DeviceFamilyPack.
Alternatively you can download MDK releases from the nRF MDK download page, as for other toolchains supported by the nRF5 SDK. First select the wanted toolchain/license combination from the dropdown. For Keil uVision 5 use "Pack". By default you are offered the latest MDK release (which is recommended,) but if for some reason you need a specific version you can select it from the radio buttons further down on the page.








\components\toolchain\modules\nrfx\mdk

Please note: You may experience that the startup c file in the Device component is from the newest (highest numbered) version of the nRF_DeviceFamilyPack on the system, while the header files are from the selected version. This is a known issue. The workaround is to make sure the pack selected in the project is the same as the highest numbered pack version installed on the system.