Apple has, until today, remained quiet about Lodsys' campaign to extract licensing fees from app developers using Apple's own in-app purchasing APIs. However, Apple senior vice president and general counsel Bruce Sewell has now sent a letter to Lodsys CEO Mark Small, insisting that Apple's license to the patent in question covers third party developers and that Lodsys should stop threatening iOS developers with "false assertions" of patent infringement.

Just over a week ago, a patent holding company called Lodsys began sending letters to iOS developers that used in-app purchasing. Those letters said that Lodsys owned the rights to US Patent #772,078, "Methods and systems for gathering information from units of a commodity across a network." The company claimed this patent was related to the in-app purchasing system used in iOS, and that developers were infringing the patent by using Apple's supplied APIs. The letters offered developers the option of paying a licensing fee or facing a lengthy and expensive lawsuit.

After receiving negative publicity over the issue, Lodsys took to its blog to outline the fact that Apple had in fact licensed the patent in question, likely through a deal with the previous holder of the '078 patent, Intellectual Ventures. However, according to Lodsys, Apple's license did not cover third-party developers.

Several developers targeted by Lodsys had forwarded the complaints they received to Apple, asking for assistance. Most believed that the patent itself was overly broad and could possibly be invalidated, but such a process is outside the financial reach of the typical small developer. Days passed without a response.

Lodsys gave developers just 21 days to respond to its threat, so developers took to pleading with Apple via a public campaign to boycott in-app purchasing APIs. To encourage Apple to step in, developers threatened to stop using in-app purchasing altogether and filed numerous bug reports against those APIs noting the potential legal pitfall.

On Monday, those developers that had contacted Apple received a copy of a letter sent from Sewell to Small outlining why Lodsys should "immediately cease its false assertions that the App Makers’ use of licensed Apple products and services in any way constitute infringement of any Lodsys patent."

In the letter, a copy of which was sent to Ars Technica by a developer, Sewell did not address the argument that Lodsys' patent may not stand up to a rigorous reexamination. Instead, he pointed out that the license that Apple holds on the '078 patent (and indeed, all four patents held by Lodsys) grants Apple the permission to offer licensed products to customers and business partners, which includes the in-app purchase APIs as well as supporting functionality provided by the iOS App Store.

Thus, the technology that is targeted in your notice letters is technology that Apple is expressly licensed under the Lodsys patents to offer to Apple’s App Makers. These licensed products and services enable Apple’s App Makers to communicate with end users through the use of Apple’s own licensed hardware, software, APIs, memory, servers, and interfaces, including Apple’s App Store. Because Apple is licensed under Lodsys’ patents to offer such technology to its App Makers, the App Makers are entitled to use this technology free from any infringement claims by Lodsys.

Sewell also noted that the infringement claims outlined in the letters that Lodsys sent to developers are "barred by the doctrines of patent exhaustion and first sale." In other words, because the technology was licensed to Apple, Lodsys has no standing to control the post-sale use of the technologies by Apple or its authorized partners, i.e. developers.

While Sewell's letter doesn't guarantee that Lodsys won't try to move forward with its threatened lawsuits, it does have developers breathing a sigh of relief. The legal theory outlined in Sewell's letter could be used in court to file a motion to dismiss any suit brought by Lodsys. Additionally, the letter itself could be a sign that Apple would be willing to file amicus briefs in support of any developer targeted over Lodsys' patents, if not launch an outright defense of the developer directly.