Question: When did the majority of the patents held by the company the Italian patents firm was representing expire?

full_context: Document 1: MP3: Technicolor (formerly called Thomson Consumer Electronics) claims to control MP3 licensing of the Layer 3 patents in many countries, including the United States, Japan, Canada and EU countries. Technicolor has been actively enforcing these patents.
Document 2: MP3: The initial near-complete MPEG-1 standard (parts 1, 2 and 3) was publicly available on 6 December 1991 as ISO CD 11172. In most countries, patents cannot be filed after prior art has been made public, and patents expire 20 years after the initial filing date, which can be up to 12 months later for filings in other countries. As a result, patents required to implement MP3 expired in most countries by December 2012, 21 years after the publication of ISO CD 11172.
Document 3: IPod: In September 2007, during a lawsuit with patent holding company Burst.com, Apple drew attention to a patent for a similar device that was developed in 1979. Kane Kramer applied for a UK patent for his design of a "plastic music box" in 1981, which he called the IXI. He was unable to secure funding to renew the US$120,000 worldwide patent, so it lapsed and Kramer never profited from his idea.
Document 4: Intellectual property: The growth of the Internet, and particularly distributed search engines like Kazaa and Gnutella, have represented a challenge for copyright policy. The Recording Industry Association of America, in particular, has been on the front lines of the fight against copyright infringement, which the industry calls "piracy". The industry has had victories against some services, including a highly publicized case against the file-sharing company Napster, and some people have been prosecuted for sharing files in violation of copyright. The electronic age has seen an increase in the attempt to use software-based digital rights management tools to restrict the copying and use of digitally based works. Laws such as the Digital Millennium Copyright Act have been enacted, that use criminal law to prevent any circumvention of software used to enforce digital rights management systems. Equivalent provisions, to prevent circumvention of copyright protection have existed in EU for some time, and are being expanded in, for example, Article 6 and 7 the Copyright Directive. Other examples are Article 7 of the Software Directive of 1991 (91/250/EEC), and the Conditional Access Directive of 1998 (98/84/EEC). This can hinder legal uses, affecting public domain works, limitations and exceptions to copyright, or uses allowed by the copyright holder. Some copyleft licenses, like GNU GPL 3, are designed to counter that. Laws may permit circumvention under specific conditions like when it is necessary to achieve interoperability with the circumventor's program, or for accessibility reasons; however, distribution of circumvention tools or instructions may be illegal.
Document 5: MP3: In February 2007, Texas MP3 Technologies sued Apple, Samsung Electronics and Sandisk in eastern Texas federal court, claiming infringement of a portable MP3 player patent that Texas MP3 said it had been assigned. Apple, Samsung, and Sandisk all settled the claims against them in January 2009.
Document 6: MP3: Sisvel S.p.A. and its U.S. subsidiary Audio MPEG, Inc. previously sued Thomson for patent infringement on MP3 technology, but those disputes were resolved in November 2005 with Sisvel granting Thomson a license to their patents. Motorola followed soon after, and signed with Sisvel to license MP3-related patents in December 2005. Except for three patents, the US patents administered by Sisvel had all expired in 2015, however (the exceptions are: U.S. Patent 5,878,080, expires February 2017, U.S. Patent 5,850,456, expires February 2017 and U.S. Patent 5,960,037, expires 9. April 2017.
Document 7: MP3: In September 2006, German officials seized MP3 players from SanDisk's booth at the IFA show in Berlin after an Italian patents firm won an injunction on behalf of Sisvel against SanDisk in a dispute over licensing rights. The injunction was later reversed by a Berlin judge, but that reversal was in turn blocked the same day by another judge from the same court, "bringing the Patent Wild West to Germany" in the words of one commentator.
Document 8: IPod: From the fifth-generation iPod on, Apple introduced a user-configurable volume limit in response to concerns about hearing loss. Users report that in the sixth-generation iPod, the maximum volume output level is limited to 100 dB in EU markets. Apple previously had to remove iPods from shelves in France for exceeding this legal limit. However, users that have bought a new sixth-generation iPod in late 2013 have reported a new option that allowed them to disable the EU volume limit. It has been said that these new iPods came with an updated software that allowed this change. Older sixth-generation iPods, however, are unable to update to this software version.
Document 9: MP3: An exception is the United States, where patents filed prior to 8 June 1995 expire 17 years after the publication date of the patent, but application extensions make it possible for a patent to issue much later than normally expected (see submarine patents). The various MP3-related patents expire on dates ranging from 2007 to 2017 in the U.S. Patents filed for anything disclosed in ISO CD 11172 a year or more after its publication are questionable. If only the known MP3 patents filed by December 1992 are considered, then MP3 decoding has been patent-free in the US since 22 September 2015 when U.S. Patent 5,812,672 expired which had a PCT filing in October 1992. If the longest-running patent mentioned in the aforementioned references is taken as a measure, then the MP3 technology will be patent-free in the United States on 30 December 2017 when U.S. Patent 5,703,999, held by the Fraunhofer-Gesellschaft and administered by Technicolor, expires.
Document 10: MP3: The basic MP3 decoding and encoding technology is patent-free in the European Union, all patents having expired there. In the United States, the technology will be substantially patent-free on 31 December 2017 (see below). The majority of MP3 patents expired in the US between 2007 and 2015.
Document 11: MP3: In September 1998, the Fraunhofer Institute sent a letter to several developers of MP3 software stating that a license was required to "distribute and/or sell decoders and/or encoders". The letter claimed that unlicensed products "infringe the patent rights of Fraunhofer and Thomson. To make, sell and/or distribute products using the [MPEG Layer-3] standard and thus our patents, you need to obtain a license under these patents from us."
Document 12: Portable media player: The first portable MP3 player was launched in 1997 by Saehan Information Systems, which sold its ``MPMan ''player in Asia in spring 1998. In mid-1998, the South Korean company licensed the players for North American distribution to Eiger Labs, which rebranded them as the EigerMan F10 and F20. The flash - based players were available in 32 MB or 64 MB (6 or 12 songs) storage capacity and had a LCD screen to tell the user the song currently playing.
Document 13: IPod: On August 24, 2006, Apple and Creative announced a broad settlement to end their legal disputes. Apple will pay Creative US$100 million for a paid-up license, to use Creative's awarded patent in all Apple products. As part of the agreement, Apple will recoup part of its payment, if Creative is successful in licensing the patent. Creative then announced its intention to produce iPod accessories by joining the Made for iPod program.
Document 14: USB flash drive: M - Systems, an Israeli company later acquired by SanDisk, filed the first patent for a USB flash drive in April 1999, known as a DiskOnKey. Later in 1999, IBM filed an invention disclosure by one of its employees. Flash drives were sold initially by Trek 2000 International, a company in Singapore, which began selling in early 2000. IBM became the first to sell USB flash drives in the United States in 2000. The initial storage capacity of a flash drive was 8 MB. Another version of the flash drive, described as a pen drive, was also developed. Pua Khein - Seng from Malaysia has been credited with this invention. Patent disputes have arisen over the years, with competing companies including Singaporean company Trek Technology and Chinese company Netac Technology, attempting to enforce their patents. Trek won a suit in Singapore, but has lost battles in other countries. Netac Technology has brought lawsuits against PNY Technologies, Lenovo, aigo, Sony, and Taiwan's Acer and Tai Guen Enterprise Co.
Document 15: IPod: iPods cannot play music files from competing music stores that use rival-DRM technologies like Microsoft's protected WMA or RealNetworks' Helix DRM. Example stores include Napster and MSN Music. RealNetworks claims that Apple is creating problems for itself by using FairPlay to lock users into using the iTunes Store. Steve Jobs stated that Apple makes little profit from song sales, although Apple uses the store to promote iPod sales. However, iPods can also play music files from online stores that do not use DRM, such as eMusic or Amie Street.
ground_truth: 2015
sub_queries: Which company was the Italian patents firm representing? Answer: Sisvel
When did the majority of the patents held by Sisvel expire? Answer: 2015