[修订]修改许可协议

README.md

@@ -125,7 +125,7 @@ RT-Thread BSP can be compiled directly and downloaded to the corresponding devel
 
 # License
 
-RT-Thread is an open source software and has been licensed under Apache License Version 2.0 since v3.1.1. License information and copyright information can generally be seen at the beginning of the code:
+RT-Thread follows the Apache License 2.0 free software license. It's completely open-source, can be used in commercial applications for free, does not require the disclosure of code, and has no potential commercial risk. License information and copyright information can generally be seen at the beginning of the code:
 
 ```c
 /* Copyright (c) 2006-2018, RT-Thread Development Team

README_zh.md

@@ -150,7 +150,7 @@ RT-Thread视频中心提供了一系列RT-Thread相关教程及分享内容。
 
 # **许可协议**
 
-RT-Thread系统完全开源，3.1.0 及以前的版本遵循 GPL V2 + 开源许可协议。从 3.1.0 以后的版本遵循Apache License 2.0开源许可协议，可以免费在商业产品中使用，并且不需要公开私有代码。
+RT-Thread 系统完全开源，遵循 Apache License 2.0 开源许可协议，可以免费在商业产品中使用，并且不需要公开私有代码，没有潜在商业风险。
 
 ```
 /*