JSFiddle - React, Tailwind, and code Playground

JavaScript

var str = 'Mozilla/5.0 (Linux; U; Android 2.2.1; en-us; device Build/FRG83) AppleWebKit/533.1 (KHTML, like Gecko) Version/4.0 Safari/533.1';

var version = str.match(/Android\s+([\d\.]+)/)[1];

console.log(parseFloat(version) < 4.1);