Question: When was the iphone 6s plus brought to the market by the developer of Proapp?

full_context: Document 1: Proapp: In Apple Inc software, a proapp is a professional application that has a distinctly different-looking GUI and look and feel from normal Apple applications and other software run on Mac OS X.
Document 2: 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 3: Final Cut Pro X: Final Cut Pro X Main editing window Developer (s) Apple Inc. Stable release 10.3. 4 / May 25, 2017; 5 months ago (2017 - 05 - 25) Written in Cocoa Operating system OS X v10. 11, macOS 10.12 Type Video editing software License Commercial proprietary software Website www.apple.com/finalcutpro/
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 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 5: 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.
Document 6: 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 7: Typography of Apple Inc.: Starting with the release of the Apple Watch, Apple has begun usage of San Francisco as the typeface of word marks such as ``iPhone '',`` AirPods'', and ``MacBook Pro ''on the devices themselves. This change is also reflected on some headlines on product marketing webpages. Apple modified the majority of its website's text to use the San Francisco font on January 24, 2017, and San Francisco became the universal official font for Apple.
Document 8: MacOS: macOS (pronounced / ˌmækoʊˈɛs /; previously Mac OS X and later OS X) is the current series of Unix - based graphical operating systems developed and marketed by Apple Inc. designed to run on Apple's Macintosh computers (``Macs ''). It has been preinstalled on all Macs since 2002. Within the market of desktop, laptop and home computers, and by web usage, it is the second most widely used desktop OS after Microsoft Windows.
Document 9: 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 10: 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 11: 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 12: 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 13: Final Cut Pro X: Final Cut Pro X Developer (s) Apple Inc. Stable release 10.4. 3 / June 21, 2018; 2 months ago (2018 - 06 - 21) Written in Cocoa Operating system macOS 10.13 Type Video editing software License Commercial proprietary software Website www.apple.com/finalcutpro/
Document 14: 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 15: Xcode: Xcode is an integrated development environment (IDE) for macOS containing a suite of software development tools developed by Apple for developing software for macOS, iOS, iPadOS, watchOS, and tvOS. First released in 2003, the latest stable release is version 10.3 and is available via the Mac App Store free of charge for macOS Mojave users. Registered developers can download preview releases and prior versions of the suite through the Apple Developer website.
ground_truth: September 25, 2015
sub_queries: Proapp >> developer Answer: Apple
when did the Apple iphone 6s plus come out Answer: September 25, 2015