You will typically need to enter your to access older versions.

is a software development suite from Arm Holdings (formerly Keil) for ARM Cortex-M based microcontrollers. Version 5.25 is a legacy release from the MDK v5.x series, which introduced software packs (CMSIS-Pack) as a key component management system.

早在2018年初，Arm公司便为5.25版本推出了两个预览版——MDK525pre和MDK525pre2，旨在提前测试并收集反馈，这为其最终的稳定性奠定了坚实基础。在正式发布后，许多开发者社区和论坛都对其给予了高度评价。例如，在硬汉嵌入式论坛的周报中就曾提到，经过数日的测试，5.25版本有效解决了5.24版本中存在的诸多问题，并推荐大家升级。MDK-ARM 5.25之所以能成为一代经典，主要得益于以下几个因素：

Arm Keil maintains an official Maintenance Portal and Product Download Archive for registered users.

Version 5.25 focused heavily on and providing deeper insights into application performance and power usage, especially when paired with the ULINKplus debug unit. Key Features and Enhancements in MDK 5.25

MDK Version 5 uses a split architecture: the IDE/Compiler toolchain is separate from the microcontroller-specific definitions (Software Packs).

This version is ideal for projects using STM32, NXP, Nordic (nRF52), and other Cortex-M microcontrollers. It was also the recommended baseline for many development environments, with some documentation specifically endorsing MDK v5.25 to v5.36 for compatibility with various software development kits (SDKs).

A new window that displays execution information, including program events, interrupt execution, data trace, and power consumption (when using the ULINKplus adapter ) .

Any you encounter during the installation or pack download phase. Share public link

. Legacy versions are generally only available to users with a valid license or an active support contract. MDK-Lite Edition:

: Added visual cues like grayed-out text for inactive #if / #endif blocks and hyperlinked symbols for quick documentation access via F1 .

MDK 5.25 the long-standing issue with Chinese characters. When the editor was set to the GB2312 encoding, developers could finally select single bytes of Chinese characters correctly, which was not possible in prior versions. However, the UTF-8 encoding issues remained and still required the user to manually save files to work around them.

Accessing previous versions requires a valid Product Serial Number (PSN) or License Code (LIC) . Once entered on the download page, you can select v5.25 from the list of available installers.