Edit: All done, we’re running 1.6.4 now, so you can upgrade normally.
1.6.4 was released this morning (our time), and we’re still working on getting everything upgraded.
The handy thing about the new launcher is that you can simply pick what version you want to play! So stick with 1.6.2 for the moment, and as soon as we can, we’ll upgrade to 1.6.4
–Rob