A YouTube spokesperson told CNET the old iOS app will continue to function indefinitely on older devices not yet upgraded to iOS 6, however iPhone 5 owners will need to download the standalone version as YouTube is no longer bundled with the new OS.
While both Apple and Google refuse to discuss the details of its YouTube partnership, it is likely that ongoing support was part of the original arrangement.
Some speculated that YouTube would drop support for the old iOS app due to Apple's mandated ad-free environment for first-party software, which limited the amount of available content as the video sharing company has recently been pushing for ad-supported videos as a means to generate additional revenue. For this reason, the new standalone YouTube app offers a wider variety of shows and the ability to subscribe to ad-supported "channels."
With sales of the new iPhone 5 expected to break records and a reportedly strong iOS 6 adoption rate, YouTube's app will likely see a flood of downloads from veteran iOS users who have become familiar with having access to the video sharing site via a dedicated app.
The ad-friendly YouTube app has been the number one most downloaded free app in the iOS App Store since its debut in September.