While the Korean server has already got the 4.5 update for some time now, the Japan and English servers are still playing catching up. Arriving on 17th December, the new class known as Gear Wing (Aethertech for English server) will add a heavy mecha vibe to the game.
I am pretty sure the Japanese players will love the Gear Wing, seeing how mecha animes and games are still flourishing as a genre. There are many Gear Wing designs, and apparently some hold different skills based on the type of keys used to activate them.
There is still no date for 4.5 to hit the English server, which has gone Free-to-Play since version 3.0, while the other Asian servers (Korea, Japan and China) have still remained as a Pay-to-Play title. A new Prestige Pack was also introduced recently, giving some slight advantages to purchasers.