Before the VirnetX case, nearly all FaceTime calls were done through a system of direct communication. Essentially, Apple would verify that both parties had valid FaceTime accounts and then allow their two devices to speak directly to each other over the Internet, without any intermediary or “relay” servers. However, a small number of calls—5 to 10 percent, according to an Apple engineer who testified at trial—were routed through “relay servers.”

Both sides in the litigation admit that if Apple routes its FaceTime calls through relay servers, it will avoid infringing the VirnetX patents. Once Apple was found to be infringing—and realized it could end up paying an ongoing royalty for using FaceTime—the company redesigned the system so that all FaceTime calls would rely on relay servers. Lease believes the switch happened in April.

via Report: After patent loss, Apple tweaks FaceTime—and logs 500,000 complaints | Ars Technica.