Google is expanding its war against 32-bit apps in Android 14

The vast majority of the Android apps you use on a day-to-day basis are either architecture agnostic or are explicitly compatible with 64-bit CPUs. Apps that don't support 64-bit CPUs are scarce nowadays, thanks to Google Play mandating back in 2019 that apps with native code include 64-bit libraries. 

However, Google couldn't immediately phase out 32-bit app support in Android, because some 32-bit apps were still widely used in heavily populated markets like China. The top Chinese app stores have already agreed to phase out the distribution of 32-bit apps, though, so there's not as much concern anymore that phasing out 32-bit app support will harm users. Dropping 32-bit support has several benefits, which is why Google is pushing to end 32-bit app support for many new devices that launch with Android 14.

The Pixel 7 and Pixel 7 Pro were the first Android phones to launch without support for 32-bit apps, but they are technically still capable of running them. This is because all the CPU cores in the Tensor G2 support the AArch32 ISA, so they should be able to run 32-bit Android apps. Google chose to build the Pixel 7's OS with a 64-bit only Zygote (the system process that all app processes are forked from), though, so apps that need 32-bit system libraries can't be started even if those libraries are included in the system image. 

The current generation Snapdragon 8 Gen 2 from Qualcomm and Dimensity 9200 from MediaTek both include CPU cores that support AArch32 (the ARM Cortex-A510r1), but the next-generation flagship chipsets from Qualcomm and MediaTek likely won't have any 32-bit-compatible CPUs as none of Arm's 2023 CPU core designs support AArch32. So while it's already expected that upcoming flagship smartphones with next-generation Qualcomm and MediaTek chipsets won't support 32-bit apps, what's surprising is that Google may mandate that all chipsets launching with Android 14 support drop 32-bit app compatibility.

When I say "chipsets launching with Android 14 support", I'm referring to chipsets where the first version of the vendor software in the Board Support Package (BSP) is built for Android 14. This is denoted by the system property "ro.vendor.api_level". For example, on a Pixel 7 Pro, this property is set to "33" which corresponds to Android 13. This is because the Tensor G2's vendor software was initially built to be compatible with Android 13. So, chipsets launching with Android 14 support would have this property set to "34".

As for how Google would check that a chipset has dropped 32-bit app compatibility, that would be done through a Compatibility Test Suite (CTS) test that checks whether the system property "ro.product.cpu.abilist32" is set. For example, here are all the ABI-related system properties on a Pixel 7 Pro. As you can see, the only NDK ABI that's listed is "arm64-v8a". In comparison, previous Pixels would also list "armeabi-v7a".

How do I know that Google is planning such a requirement? Last week, I spotted a post on the Google Issue Tracker from a Xiaomi engineer that talks about a requirement in VSR. VSR stands for Vendor Software Requirements, a document that enumerates all the requirements that the vendor software of an Android device has to meet in order to pass Google certification.

Based on this Issue Tracker post, it seems that Xiaomi is having trouble passing CTS on a device because they want to keep 32-bit app support on an upcoming device that launches with Android 14. The CTS test that Xiaomi's device is failing is based on the requirement defined in VSR-3.12-002, which according to a source, states the following:

CHIPSETS launching with Android 14 or higher:

• MUST support only 64-bit NDK ABIs (arm64-v8a and/or x86_64).
• MUST NOT support 32-bit NDK ABIs (armeabi-v7a or x86)

This requirement is surprising, because it'll mean that even new budget and mid-range chipsets with 32-bit CPU cores won't be allowed to ship with 32-bit NDK ABI support and thus won't be able to run 32-bit Android apps. It's possible the requirement isn't finalized, though, as Google is known to delay or even suspend requirements based on feedback they get from partners. Given that the Xiaomi engineer posted the report on August 25 and Google closed the issue on September 11, though, it seems likely the requirement is still in place. 

A silver lining for those of you who might still want to run some 32-bit apps is that there are software solutions to make that happen even on 64-bit only CPUs or OS builds. For example, an AArch32-to-AArch64 binary translator would make it possible to run 32-bit Android apps on 64-bit-only Arm devices. MediaTek may be testing this out, though it's unclear if Google will approve of it. 

Looking ahead to Android 15, I wouldn't be surprised if Google further restricts what devices are allowed to run 32-bit apps. At the very least, it's likely that Android 15 will introduce a warning when users try to run 32-bit apps on their devices.