Why are people commenting on separating paid F from upgrades? That's not what the OP said at all. To answer the question asked, the new boarding order is military first (pointless, IMO), then, in one group, F, GS, PPlat, Plat and 1K. After that is *Gold, Gold, etc.

It hasn't really made a huge difference to the level of chaos at the gate in my experience - although the concept of gate lice has become a constant source of amusement for me since I started flying more UA metal - but on elite-heavy routes it can get a bit swamped at the beginning.