Though Quarterly security update of Adobe Reader has targeted at fixing critical vulnerabilities and offering improvements, significant news is Adobe Reader 11.0.07 version no longer works in Windows XP (and Office 2003 as well), welcoming news is support for Windows 8.1 Update has been added to the the latest release.

Remove Adobe Reader 9, X and XI with Official Adobe Reader and Acrobat Cleaner Tool

Adobe Reader Now Lets You Sign Your PDF Documents Easily

Adobe Reader XI version 11.0.07

Adobe Reader 11.0.07 Adds Support for Windows 8.1 Update, and Drops for Windows XP

Support added for:

  • Windows 8.1 Update 1
  • Macintosh 10.9.2

Adobe Reader XI Available with Windows 8 Support [Offline Installer]

Support Dropped for :

Windows XP and Office 2003
MS Office 2003 PDFMakers

"Microsoft is ending support for Windows XP and Office 2003 on April 8, 2014. This means the following for Acrobat products: Support for Acrobat & Reader versions X & XI on Windows XP will end with the May, 2014 quarterly update. You can continue to install and update Acrobat and Reader on XP, but future updates will not have been tested on XP and technical support will end for that platform.Dropped support for MS Office 2003 PDFMakers."release notes informs.

How to Turn off/disable Protected Mode in Adobe Reader X

You can disable AdobeARM.exe but not the reader_sl.exe, Why?

Check Adobe Reader release notes for fixes, improvements, new features and known issues.