If migrating from ARM Compiler 5 (AC5), ensure your compiler settings are configured for "AC6" and update your linker script ( .sct ) accordingly.

There are two primary methods to obtain the official installer: via the official Keil website or through direct download links.

The public "Product Downloads" page typically provides the most recent version (e.g., v5.42a). To obtain an older specific version without a license, you may need to contact a local distributor or Keil support directly. Key Features of Version 5.25

Use the latest possible CMSIS packs for your project to leverage the best performance, even if using an older IDE version.

: Version 5.25 is notable as it was the last version to feature a specific Legacy Support

Open µVision as an administrator and go to File > License Management to register your Lite, Community, or Professional license . Keil Product Downloads Downloads * MDK-Arm. MDK Version 5.25 - Arm Developer