More on IE's UA string and the SV1 token

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More on IE's UA string and the SV1 token

  • Comments 49

In earlier posts, Christopher mentioned that for Windows XP SP2 and Windows Server 2003 SP1  the UA string was getting a new ‘SV1’ decorator.

This has stirred up a flurry of questions and comments about our reasoning behind this decision.

Why did we add ‘SV1’ instead of update the IE version number?  Well, we know from past experience that changing the version number can have a huge impact on site and application compatibility.  We felt that since IE for XPSP2 and WS03SP1 does not have significant changes to page rendering, DHTML, the object model, and the like, the level of impact on the Web of an IE version number change was not justified.   So adding “SV1” seemed a reasonable compromise between no changes to the UA string and a version number change.

The leads to the question, what’s in store for the SV1 tag? At some point in the future, we’ll want to release the next round of security improvements that are, for example, as far beyond XPSP2 as XPSP2 was beyond XPSP1.  If this was part of a release that did change the platform (rendering, DHTML, object model, etc), then we would probably change the version number, otherwise we probably simply change “SV1” to “SV2.”   We might remove SV1 if we do update the IE version.

We certainly welcome feedback on whether you feel we took the right approach.  We’d also like your opinions on the question “should ‘SV1’ stay even if the version number changes?”

- Bruce

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