Google gave an equally vague answer to questions about which phones might be upgraded and if any of them had hardware limitations that might prevent an upgrade. "Because Android is open source, all software updates we release are available for carriers and handset makers to take and update their current or future Android-powered devices," Katie Watson, a Google spokeswoman said via e-mail. She also pointed out that the updated OS hasn't been released so no devices can be updated yet. - Jeff Jarvis