I would like to know how many iOS 3.2 (and presumably below) users are accessing my website. The reason is because iOS 3.2 had a maximum cache limit of around 25.6k, and files larger than this size would not be cached. This is according to http://www.yuiblog.com/blog/2010/06/28/mobile-browser-cache-limits/

We use both awstats and Google Analytics. Unfortunately neither gives the iOS version. awstats simply reports Mac OS X and the Safari version. Google Analytics does not report the version of the operating system either, but gives the Safari versions in great refinement.

A solution to this question would be a mapping of which Safari versions indicated iOS 3.2, or simply which Safari versions had the 25.6k cache limit.


I don't think I've ever seen an official listing of versions, so you'll have to piece things together a little.

For your immediate question, there's a page in the Safari Web Content Guide that uses the 3.2 UserAgent string as an example, and gives it as "Mozilla/5.0 (iPad; U; CPU OS 3_2 like Mac OS X; en-us) AppleWebKit/531.21.10 (KHTML, like Gecko) Version/4.0.4 Mobile/7B334b Safari/531.21.10" which I'm assuming you can take as canonical.

In the more general case:
From Casey Fleser, an iOS Release / Mobile Safari Version Table. He doesn't mention what his sources are, but it's worth noting a slight discrepancy with the Wikipedia iOS version history page, (You'll have to pop open the gray "Table of versions: iOS 3.x" bar) which doesn't doesn't show the WebKit version upgraded to 531.21.10 until iOS 3.2.1 but that's probably not a significant concern unless chasing some very specific bug.

  • You point out something that can adapted. Our site already is using the user agent string but is just extracting the Safari version. But if 531.21.10 thus indicates 3.2, then that would give the answer. The other pages you mention are useful, but alas do not give the mapping, afaik. Jan 12 '12 at 17:43
  • Not sure I follow. The Flesler table has the browser version over in the far right column. Matched with the green area in the interior, you can see what group of iOS devices had it available. Or am I misinterpreting something in your question?
    – Su'
    Jan 12 '12 at 22:19

I ran into a variation of this same question yesterday. Digging into the links given in the other answer a bit, I came to the Safari versions page, and I wish I had been looking at this page yesterday. I was exporting to Excel CSV the data I was looking at (Browser Version>Safari) and was using user agent string sites to match up versions. I was looking to map all the Safari versions used by any iPhone/iPod/iPad of any generation, but on to your answer...

I think you are right to presume the iOS3.2 or earlier, but more research could confirm that. You could then export data of all Safari versions and then look at just those versions of Safari that have Safari (525.28 or earlier if I am reading right) You could then write a formula to yank all the data for only those versions into another spot in the spreadsheet/worksheet to isolate or do further analysis on.

  • You may find this page of interest.
    – Dallas
    Jan 14 '12 at 18:15

It turns out there is a revised version of the original research, found at this updated page


This revised page states that the original limits were based upon a faulty methodology, and the real limits are either 1MB or 4MB, depending. So the original 25.6K limit is irrelevant.

The article explains that that limit does apply to HTML, but not to CSS or Javascript. So as far as I am concerned, the whole this is a moot point, and there is no longer any need for me to detect old iOS versions.

Some of the info in the answers may still be relevant if you are concerned with the caching of HTML.

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

Not the answer you're looking for? Browse other questions tagged or ask your own question.