Backward Compatibility of 16 KB ELF Alignment with Older Android Versions

[IBKR-MiltonLee]

Question: Backward Compatibility of 16 KB ELF Alignment with Older Android Versions

Hi all,

I’m distributing an SDK to customers using the Android NDK, and I have a question about the upcoming 16 KB page size requirement that Google is enforcing starting November 2025.

According to the AOSP doc here:
https://source.android.com/docs/core/architecture/16kb-page-size/16kb

“Android 15 and higher have support for building Android with a 16 KB ELF alignment, which works with 4 KB and 16 KB kernels starting with android14-6.1.”

This makes it clear that on Android 15+ with 16 KB kernels, 16 KB ELF alignment works as expected.

But here’s my main concern:
👉 If I build native libraries (.so) with 16 KB ELF alignment, is there an official guarantee or statement from Google that these binaries will still run correctly (fall back to 4 KB) on older Android versions (Android 7–14)?

I plan to test this myself (building arm64 ABI with NDK r28 and running on Android 9–14 consumer phones), but many of our customers use customized/industrial Android devices. Without an official confirmation from Google, I expect customers will raise a lot of questions about backward compatibility.

So my question is:

• Is there any official Google documentation or blog post that explicitly states that 16 KB built libraries are backward compatible with older Android versions (4 KB page size kernels)?

Thanks in advance!

[DanAlbert]

Prior to 16KiB alignment, Android required 4KiB alignment. 16 is a multiple of 4, so all your 16KiB aligned things are by definition 4KiB aligned.