There are 3 prestige levels; Bronze, Silver and Gold. One can earn the first prestige medal (Bronze) on crossing level 100 the first time, Silver the 2nd time and Gold the 3rd and last time. All weapon stats remain maxed out on unlocking them once, even if you start a new prestige level from level 1. Your prestige medal achievement will be displayed on the scoreboard beside your rank and on F1 > stats.
There will be a lot more bonus features for players with prestige level 3 (Gold) medals such as exclusive vehicles, skins, permanent vips etc. But since these bonus features have not been added yet, it's not official as to what the exact features would be. You'll all be updates here once they are added.
Following this update we've come to the decision of removing XP sharing among players in a party chat. It has to be understood that a player's skill is gained though his/her experience on the server and it makes no sense when one player boosts the XP of another player via party chat. This decision is better to be made knowing there are players who understand why it's being removed, hence, the poll above.