The simple answer is yes!
With the release of Apple’s iOS 10.2.1 Apple implemented a 'feature' to the iPhone 6, iPhone 6s and iPhone SE to resolve an issue where the iPhones with older batteries would unexpectedly shut down.
This would happen during peak demands on your battery in cold conditions, batteries with low charge or older batteries. With the release of Apple’s iOS 11.2 Apple has extended this to the iPhone 7.
Apple's position is that it is not slowing the iPhones down to encourage an upgrade but is addressing an issue with older batteries. These iPhones were unexpectedly shutting downing in order to limit damage to the internal components.
This issue also occurs in extreme cold or hot weather and was recently highlighted with the shiny new iPhone X shutting down in extremely cold conditions. It makes sense to slightly slow these iPhones with degraded batteries down to avoid embarrassing and inconvenient shutdowns.
Apple has released a statement regarding the feature:
"Our goal is to deliver the best experience for customers, which includes overall performance and prolonging the life of their devices. Lithium-ion batteries become less capable of supplying peak current demands when in cold conditions, have a low battery charge or as they age over time, which can result in the device unexpectedly shutting down to protect its electronic components.
Last year we released a feature for iPhone 6, iPhone 6s and iPhone SE to smooth out the instantaneous peaks only when needed to prevent the device from unexpectedly shutting down during these conditions. We’ve now extended that feature to iPhone 7 with iOS 11.2, and plan to add support for other products in the future."
UPDATE: Apple has announced a reduction to the price of iPhone battery replacements from $119 to $39 in Australia.
A message from Apple on the 28th of December 2017:
"Apple is reducing the price of an out-of-warranty iPhone battery replacement by A$80 — from A$119 to A$39 — for anyone with an iPhone 6 or later whose battery needs to be replaced, available worldwide through to December 2018. Details will be provided soon on apple.com/au.
Early in 2018, we will issue an iOS software update with new features that give users more visibility into the health of the battery in their iPhone, so they can see for themselves if its condition is affecting performance.
As always, our team is working on ways to make the user experience even better, including improving how we manage performance and avoid unexpected shutdowns as batteries age."