M README.md → README.md

@@ -3,7 +3,7 @@ Simple x86 operating system written in assembly and C.
 
 ## Software Requirements
 * GNU make
-* GCC 7 (or higher) Cross Compiler + matching binutils, tailored for freestanding i686-elf-targets
+* GCC Cross Compiler + matching binutils, tailored for freestanding i686-elf-targets
 * Doxygen: If you want to build the documentation
 
 ## Make commands
@@ -17,4 +17,10 @@ ### Clear output directories
 ```make clear```
 
 ### Build documentation:
-```make docs```+```make docs```
+
+## Tested build environment versions
+### 2023-03-01
+* GCC 12.2.0
+* binutils 2.40
+* QEMU 4.2.1