Yes, you can. raylib comes compiled by default for OpenGL 3.3 backend but it can be recompiled for older OpenGL versions! It can be recompiled for OpenGL 1.1 (1997) and OpenGL 2.1 (2006). To do that using Notepad++, just follow this steps:
1. Open file `C:\raylib\raylib\src\core.c`
1. Open scripts execution window (F6)
2. Execute Notepad++ script: `raylib_source_compile` but choose the desired OpenGL API version: