Fewer iPhone Users Are Updating to iOS 26 Than iOS 18

Apple’s latest mobile operating system, iOS 18, currently maintains an adoption rate of approximately 79% among active iPhone users, according to recent data from Apple’s Developer Support page. While this figure reflects steady transition patterns, industry analysts note that adoption speed has slowed slightly compared to the rollout of previous versions, such as iOS 17.

Current iOS Adoption Trends

As of February 2025, Apple reports that 79% of all devices introduced in the last four years are running iOS 18. An additional 17% of these devices remain on iOS 17, while 4% continue to run earlier versions of the software. When looking at the entire active install base—including older hardware no longer eligible for the latest updates—the adoption rate sits at 73%.

These statistics are tracked by Apple through the App Store, which monitors device versions connecting to the platform. By providing this data, Apple offers developers a clear picture of which APIs and system features are available to the majority of their user base.

Why Adoption Rates Are Shifting

The slight cooling in update velocity is largely attributed to the nature of recent software cycles. According to market intelligence firm Mixpanel, users often wait for "dot" releases—such as iOS 18.1 or 18.2—before upgrading. These mid-cycle updates frequently include the most stable versions of marquee features, such as the initial rollout of Apple Intelligence tools.

Historically, adoption spikes coincide with major feature releases. When Apple introduces significant privacy changes or new interface paradigms, users tend to update more aggressively. In contrast, cycles focused on performance refinement and under-the-hood optimization often see a more gradual adoption curve.

Impact on App Development

For software developers, the 79% adoption rate serves as a critical benchmark. Maintaining compatibility with the previous version (iOS 17) remains standard practice, as that segment still represents a significant portion of the total user population.

• Targeting the majority: Developers can safely implement iOS 18-exclusive frameworks for the vast majority of their users.
• Legacy support: The 4% of users on older OS versions typically represent older hardware, requiring developers to weigh the cost of maintenance against the potential user reach.
• Feature gating: Most modern apps use “feature flagging” to deliver specific experiences based on the user’s OS version, ensuring the app doesn’t crash on older software.

Looking Ahead to iOS 19

Apple typically announces its next major iteration, iOS 19, during the Worldwide Developers Conference (WWDC) in June. As the company prepares for this transition, the focus will shift toward how well iOS 18 has integrated its AI-driven capabilities into the broader ecosystem. If the current trend holds, Apple will likely maintain this 70% to 80% adoption range for the remainder of the iOS 18 lifecycle, providing a stable foundation for the next wave of software updates.