updated 07:40 pm EDT, Tue October 29, 2013
Only visible external improvement to Glass is a mono earbud
Just one day after Google expanded its Glass Explorers program for the eponymous wearable device, the search engine displayed a minor evolution of the product. The only obvious change to the device is the addition of a single monaural earbud, connecting to the main device through the charging and synchronization micro-USB port.
The official blog post on the topic gave little information on the improvements, but common complaints of adopters include delicacy of the product, as well as the lack of earbud (which has now been rectified).
Alongside yesterday's growth of the Explorer's program, Google also announced its intention to allow first-round purchasers to swap out the first iteration of the product for a newer revision, presumably upon retail release. No specific details on the exchange are known, but the program will be detailed likely before the end of the year.