On Thu, Dec 17, 2009 at 09:08:50AM +0100, Massa, Harald Armin wrote:
> I experienced similiar problems with expires: -1 just recently.
>
> Crazy thing: that applications have been in duty for > 6 years; and
> suddenly expires: -1 did not prevent caching anymore. With browsers
> IE7, IE8 and Firefox.
>
> What DID help was expires: 0

Is it possible for you to test with

    Expires: -1
    Cache-Control: max-age=0, must-revalidate

I'd rather not change the Expires header at this point (cargo cult
programming, I know).

> I had to fix it in a rush; would be interested if expires: 0 instead
> expires: -1 is a change that also resonates with your usage.

Yes but I'm not sure I can test it though since it's a customer
behind a corporate firewall.

Regards,

  Neil