What version of ruby is RMXP/RMVX?

[Daxis]

I'm about to seriously start learning scripting for once. Ruby is going to be the one I'm going to learn, and I think that using RMXP and RMVX is going to be good practice. However, before I buy the book or whatever, I want to know, what's the version of ruby is rmxp?

Okay, I get that RMXP and rmvx uses there own sorta type of ruby, but both were from different times. Although I'm pretty sure that just learning version whatever of ruby won't allow me to use rmxp, it would be a good threshold to start adapting to rmxp. However, which versions would xp and vx be most compatible with?

 

[vgvgf]

Both RMXP and RMVX use Ruby 1.8.1(Almost identicaly to 1.8.6), but some features are disabled. The most noticeable diference is that RPG Maker can't load .so files with require, but you can still make lots of things without that.