[yuanchuan]

Correct me if I'm wrong. I watched the Safari Content Blocker video that is presented in WWDC 2015 and it mentioned that the list of content to be filtered is compiled to bit code instead of reading it as a JSON file, which makes it more efficient and less draining on CPU. Since it is compiled down to bit code, 32-bit will not be compatible to 64-bit and that's why only the newer iPhones and iPads are compatible. It is not that iPhone 5 is not powerful enough but simply the CPU architecture doesn't support.

[toyg]

That's the most artificially overengineered solution I've seen in a while. Since the adblock list is custom, it would have to be "compiled" on the phone anyway, so arch mismatch simply doesn't apply. Even if it did, it could be done at phone startup. It's "compiling" a list of strings, not building an office suite...

There are so many high-performance/low-power ways to solve the extremely complicated problem of "does a given string appear in a given list?"... this is just Apple looking for excuses to force people on 5 to upgrade, as usual.

[kalleboo]

If Apple was looking for excuses to force people on 5 to upgrade, they'd simply not support iOS 9 on that device at all...

[vbezhenar]

Supporting old devices is kind of marketing against Android. How those devices actually work with new OS is another matter.

[kccqzy]

They would need to be compiled to a different architecture. Guess Apple doesn't want to write the code to compile the list to older 32-bit ARM.