Original sentence: Some players however exploited the opportunity to continue use 1.5 on an alternative WON network, not operated by Valve.Today, 1.6 is the CS variant with the biggest population, although a small pocket of players are sticking with 1.5 even today.Valve turned off WON in mid 2004, forcing the vast majority of the players to upgrade to 1.6
Edited sentence: Until today, 1.5 is the most popular variant of Counter-Strike.Valve turned off WON in mid 2004, forcing some amateur players to upgrade to Steam initially, but allowing more professional players an opportunity to circumvent Valve and continue building 1.5's popularity