If your iPhone’s battery seems to be vanishing faster than usual after installing iOS 27, Apple says there is a simple reason that your phone may still be busy working on the update even after the installation appears to be complete.
Apple’s latest support guidance says users who notice reduced battery life after an update should “wait a few days and then check again”. A major iOS upgrade can trigger background activity such as indexing data and files, downloading assets, updating apps and completing other system tasks, all of which can temporarily affect battery life and thermal performance. The company has even added an ‘Ongoing iOS Update’ insight under Battery settings to show when such activity is still taking place.
But with iOS 27 bringing more AI and system-level features to the iPhone, the battery drain is only the beginning of a bigger question that as smartphone software gets smarter and more demanding, how long can older hardware keep up? A major operating system update is no longer just about a redesigned interface or a handful of new settings. Apple’s latest update pushes Siri into the operating system, adds new Apple intelligence capabilities and changes how users interact with search, system apps and other parts of the phone. This can make a newer iPhone feel more capable, while exposing the limitations of an older model.
Battery health adds another complication. Apple notes that rechargeable batteries have a limited lifespan and may eventually need replacement. So when an older phone gets a new operating system, it is effectively dealing with two separate pressures: ageing hardware and newer software demands.
The distinction matters even more as artificial intelligence moves from being something users open as an app to something embedded throughout the operating system. Some of the functions rely on processing capabilities that are available only on newer hardware and that is where the meaning of a “supported” phone gets complicated. An older iPhone can be eligible for iOS 27 without getting every feature that Apple is promoting with the update. Apple Intelligence requires compatible hardware, including the iPhone 15 Pro and 15 Pro Max and iPhone 16 models and later. So a phone can be supported without being fully capable.
This upgrade shift is not limited to Apple. Google has been extending the software life of its devices. For example, the Pixel 8 and Pixel 8 Pro, launched in 2023, were promised seven years of software support, including Android OS upgrades, security updates and Feature Drops. Google said it was seeing people use Pixel phones “longer and longer” and also committed to making parts available for seven years. Google’s current policy extends the seven-year update commitment to Pixel 8 and later devices.
Samsung has taken a similar approach. Its Galaxy S26 series comes with seven generations of OS upgrades and seven years of security updates, while the Galaxy S26 FE also gets seven generations of OS upgrades and seven years of security updates.
The longer support window is significant because if a phone continues receiving operating-system and security updates for seven years, consumers have less reason to replace it simply because its software has aged out.
So when does a phone actually become too old? There is no particular number, (though some would shout 3-4 years old models). A smartphone has several things running at a time such as how long apps continue to work on its system, how capable are its processor and memory, and how is the battery life faring.
A four-year-old phone could remain usable while missing certain AI features available on newer models. Similarly, a new phone with a degraded battery or limited storage can become frustrating to use even while it remains fully supported. This also changes the question of whether users should install every update the moment it arrives.
Security updates are different from major feature upgrades as they help protect personal information, accounts and payments by fixing any vulnerabilities. Major operating-system releases bring larger changes which sometimes initially introduce bugs or temporary battery and heating issues. Hence for users with older phones, it makes sense to look beyond the version number and check what the update actually brings to their model. There is little benefit in rushing to install a headline feature if the hardware cannot support it. The phone may not necessarily become “too old to use” when a new update arrives but the gap between the new software promise and old hardware can widen over time.