Close to 8 per cent (187,000) of the approximately 2.4 million apps on the App Store may not work on iOS 11 if they are not written for the 64-bit processers used in Apple’s smartphones since the iPhone 5S, Sensor Tower said.

Early last month, developers working with the beta version of iOS 10.3 discovered a warning dialogue stating this could happen.

“The expectation that Apple will remove 32-bit app support in iOS 11 is based on beta software, so we won’t truly know if these apps will be relegated to the history books until the latest version of iOS launches this fall,” the report stated.

Even if the apps are dropped, it is still possible for developers to update them.

The iOS ecosystem saw 64-bit apps introduced with the launch of Apple’s A7 processor in the iPhone 5S. Apple introduced guidelines calling for all new apps submitted for approval to support 64-bit processors by February 1, 2015 and stated that it would reject 32-bit-only app updates as of June, 2015.

“It’s likely that Apple is aiming to reduce the “bloat” and increase the performance of future iOS versions on new 64-bit devices with this (potential) move,” the report said.

Games accounted for about 38,600 of the approximately 187,000 apps not updated for 64-bit processors (see image below, click image enlarge).

The games category was followed by education, entertainment, and lifestyle.

For many apps, especially those with very few downloads, the small amount of effort required to update them may not be worthwhile, the report said.

For some, it will be requests from loyal users that prompt an update.

Apple has been working to purge its platform of broken or unsupported apps in recent months, separately from its initiative to encourage 64-bit compatibility. Last year Sensor Tower found 16 per cent of apps hadn’t been updated in more than three years and Apple removed at least 47,000 apps from the store.