If you've been prompted to install an Adobe Reader update in the last couple of days, I'd go ahead: it's to fix a rather nasty security bug.
A vulnerability report was made public yesterday
Thankfully, the APL team followed reasonable reporting practices and reported the issue to Adobe; with forewarning about the issue before it becomes common knowledge the company was able to work on a advisory
of their own, as well as the all-important patch to render the bug harmless.
Coming less than a month after a similar scripting language flaw was revealed in the Flash Player
also produced by Adobe, it's clear that the company is going to have to do a bit of work on its image in the computer security world.
If you don't want to wait for your copy of Adobe Reader to prompt you, links to download updates for all affected versions are available on the Adobe website