Sprint's Wi-Fi offloading partner Boingo Wireless said that roughly 22 million Sprint customers are now moving onto Boingo's Wi-Fi network in dozens of U.S. airports across the country. The company added that it is now supporting all of Sprint's iOS and Android phone customers, and that Boingo plans to expand support to Sprint's sub-brands, which likely include the company's prepaid brands like Boost Mobile and Virgin Mobile. Boingo said it eventually expects to support up to 40 million total Sprint customers. Boingo also reiterated that another tier-one U.S. wireless carrier would join Sprint in offloading its traffic to Boingo's Wi-Fi networks sometime in the first half of this year. "I think the big learning has been the notion of carrier quality or carrier grade is a critical component to rolling this out.