Question: When did the M4V developer's iPhone 6S plus come out?

full_context: Document 1: IPhone 6S: The iPhone 6S and iPhone 6S Plus (stylized and marketed as iPhone 6s and iPhone 6s Plus) are smartphones designed, developed and marketed by Apple Inc. They were announced on September 9, 2015, at the Bill Graham Civic Auditorium in San Francisco by Apple CEO Tim Cook, with pre-orders beginning September 12 and official release on September 25, 2015. The iPhone 6S and 6S Plus were succeeded by the iPhone 7 and iPhone 7 Plus in September 2016.
Document 2: Apple ProRes: Apple ProRes is a high quality, lossy video compression format developed by Apple Inc. for use in post-production that supports up to 8K. It is the successor of the Apple Intermediate Codec and was introduced in 2007 with Final Cut Studio 2. It is widely used as a final format delivery method for HD broadcast files in commercials, features, Blu-ray and streaming.
Document 3: IPhone 6: The iPhone 6 and iPhone 6 Plus are smartphones designed and marketed by Apple Inc. It is the eighth generation of the iPhone, succeeding the iPhone 5S that were announced on September 9, 2014, and released on September 19, 2014. The iPhone 6 and iPhone 6 Plus jointly were themselves replaced as the flagship devices of the iPhone series by the iPhone 6S and iPhone 6S Plus on September 9, 2015. The iPhone 6 and 6 Plus include larger 4.7 and 5.5 inches (120 and 140 mm) displays, a faster processor, upgraded cameras, improved LTE and Wi - Fi connectivity and support for a near field communications - based mobile payments offering.
Document 4: IPhone 7: iPhone 7 and iPhone 7 Plus are smartphones designed, developed, and marketed by Apple Inc. They were announced on September 7, 2016, at the Bill Graham Civic Auditorium in San Francisco by Apple CEO Tim Cook, and were released on September 16, 2016, succeeding the iPhone 6S and iPhone 6S Plus as the flagship devices in the iPhone series. Apple also released the iPhone 7 and 7 Plus in numerous countries worldwide throughout September and October 2016. They were succeeded as flagship devices by the iPhone 8 and iPhone 8 Plus on September 22, 2017, and the iPhone X on November 3, 2017.
Document 5: 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.
Document 6: IPod: The iPod line can play several audio file formats including MP3, AAC/M4A, Protected AAC, AIFF, WAV, Audible audiobook, and Apple Lossless. The iPod photo introduced the ability to display JPEG, BMP, GIF, TIFF, and PNG image file formats. Fifth and sixth generation iPod Classics, as well as third generation iPod Nanos, can additionally play MPEG-4 (H.264/MPEG-4 AVC) and QuickTime video formats, with restrictions on video dimensions, encoding techniques and data-rates. Originally, iPod software only worked with Mac OS; iPod software for Microsoft Windows was launched with the second generation model. Unlike most other media players, Apple does not support Microsoft's WMA audio format—but a converter for WMA files without Digital Rights Management (DRM) is provided with the Windows version of iTunes. MIDI files also cannot be played, but can be converted to audio files using the "Advanced" menu in iTunes. Alternative open-source audio formats, such as Ogg Vorbis and FLAC, are not supported without installing custom firmware onto an iPod (e.g., Rockbox).
Document 7: IPhone 6: The iPhone 6 and iPhone 6 Plus are smartphones designed and marketed by Apple Inc. The devices are part of the iPhone series and were announced on September 9, 2014, and released on September 19, 2014. The iPhone 6 and iPhone 6 Plus jointly serve as successors to the iPhone 5S and were themselves replaced as flagship devices of the iPhone series by the iPhone 6S and iPhone 6S Plus on September 9, 2015. The iPhone 6 and 6 Plus include larger 4.7 and 5.5 inches (120 and 140 mm) displays, a faster processor, upgraded cameras, improved LTE and Wi - Fi connectivity and support for a near field communications - based mobile payments offering.
Document 8: M4V: The M4V file format is a video container format developed by Apple and is very similar to the MP4 format. The primary difference is that M4V files may optionally be protected by DRM copy protection.
Document 9: USB: Media Transfer Protocol (MTP) was designed by Microsoft to give higher-level access to a device's filesystem than USB mass storage, at the level of files rather than disk blocks. It also has optional DRM features. MTP was designed for use with portable media players, but it has since been adopted as the primary storage access protocol of the Android operating system from the version 4.1 Jelly Bean as well as Windows Phone 8 (Windows Phone 7 devices had used the Zune protocol which was an evolution of MTP). The primary reason for this is that MTP does not require exclusive access to the storage device the way UMS does, alleviating potential problems should an Android program request the storage while it is attached to a computer. The main drawback is that MTP is not as well supported outside of Windows operating systems.
Document 10: IPhone 6S: iPhone 6S and iPhone 6S Plus (stylized and marketed as iPhone 6s and iPhone 6s Plus) are smartphones designed, developed and marketed by Apple Inc. They were announced on September 9, 2015, at the Bill Graham Civic Auditorium in San Francisco by Apple CEO Tim Cook, with pre-orders beginning September 12 and official release on September 25, 2015. The iPhone 6S and 6S Plus were succeeded by the iPhone 7 and iPhone 7 Plus in September 2016.
Document 11: IPhone 7: iPhone 7 and iPhone 7 Plus are smartphones designed, developed, and marketed by Apple Inc. They were announced on September 7, 2016, at the Bill Graham Civic Auditorium in San Francisco by Apple CEO Tim Cook, and were released on September 16, 2016, succeeding the iPhone 6S and iPhone 6S Plus as the flagship devices in the iPhone series. Apple also released the iPhone 7 and 7 Plus in numerous countries worldwide throughout September and October 2016. They were succeeded as flagship devices by the iPhone 8 and iPhone 8 Plus on September 22, 2017 and the upcoming iPhone X on November 3, 2017.
Document 12: IFrame (video format): iFrame is a digital video format developed by Apple. It is based on existing industry standards, such as AVC/H.264, AAC and QuickTime, and can be used with compatible Mac and PC applications.
Document 13: IPhone 7: iPhone 7 and iPhone 7 Plus are smartphones designed, developed, and marketed by Apple Inc. They were announced on September 7, 2016, at the Bill Graham Civic Auditorium in San Francisco by Apple CEO Tim Cook, and were released on September 16, 2016, succeeding the iPhone 6S and iPhone 6S Plus as the flagship devices in the iPhone series. Apple also released the iPhone 7 and 7 Plus in numerous countries worldwide throughout September and October 2016. They will be succeeded as flagship devices by the iPhone 8 and iPhone 8 Plus on September 22, 2017 and the iPhone X on November 3, 2017.
Document 14: IPod: At the time the store was introduced, purchased audio files used the AAC format with added encryption, based on the FairPlay DRM system. Up to five authorized computers and an unlimited number of iPods could play the files. Burning the files with iTunes as an audio CD, then re-importing would create music files without the DRM. The DRM could also be removed using third-party software. However, in a deal with Apple, EMI began selling DRM-free, higher-quality songs on the iTunes Stores, in a category called "iTunes Plus." While individual songs were made available at a cost of US$1.29, 30¢ more than the cost of a regular DRM song, entire albums were available for the same price, US$9.99, as DRM encoded albums. On October 17, 2007, Apple lowered the cost of individual iTunes Plus songs to US$0.99 per song, the same as DRM encoded tracks. On January 6, 2009, Apple announced that DRM has been removed from 80% of the music catalog, and that it would be removed from all music by April 2009.
Document 15: IPhone 6: The iPhone 6 and iPhone 6 Plus are smartphones designed and marketed by Apple Inc. The devices are part of the iPhone series and were announced on September 9, 2014, and released on September 19, 2014. The iPhone 6 and iPhone 6 Plus jointly serve as successors to the iPhone 5S and were themselves replaced as flagship devices of the iPhone series by the iPhone 6S and iPhone 6S Plus on September 9, 2015.
ground_truth: September 25, 2015
sub_queries: M4V >> developer Answer: Apple
when did the Apple iphone 6s plus come out Answer: September 25, 2015