In order to get the best performance out the Cortex-M7 processor, a number of C compilers and their runtime libraries have been optimized and updated.
In addition, a number of changes in the debug system for the Cortex-M7 processor compared to Cortex-M4 means that software developers must update their tool chain to a newer version in order to debug applications on Cortex-M7 based microcontroller products. In a few cases, the firmware on the debug adaptor might also need an update.
As a result, an update to latest development tool chain is strongly recommended.
Keil MDK officially supports the Cortex-M7 starting with version 5.12