Google has yet to offer a public launch date for Glass, however they recently began opening the Explorer program a bit. Basically, hinting the program is going smooth. Anyway, Google mentioned that existing Explorers would be able to invite up to three more friends into the world of Glass. And along with that, there was also mention of updated hardware.
At the time, Google didn't offer much in terms of when we could expect the updated hardware to begin arriving. They did post an image showing Google Glass v2 shortly after the announcement, but now it looks like the units have begun arriving for users. Det Ansinn of BrickSimple LLC has recently shared some images on his Google+ page.
Perhaps more important though, along with a real-world style image of Glass v2 being worn -- we are beginning to get some details on the hardware. For example, there was mention of how the earbud will work with the old devices and about how the bone conduction remains the same. Nathan Russak, also of BrickSimple LLC said; "The earbud is simply an optional accessory for when you want some additional volume (for phone calls, etc) since the bone conduction speaker is pretty quiet."
While the new hardware sounds like a good option for those getting invited into the Explorer program now, there is the question as to whether existing Explorers should update. Of course, that is a personal decision and we suspect extending the length of the warranty (by getting new Glass) could be beneficial, but otherwise, it seems as if the hardware is largely the same.
To that point, both Ansinn and Russak had similar comments on the new hardware. Ansinn mentioned how "there are no obvious physical changes with the hardware" and Russak said there is "no noticeable physical change to the device."