For example, release 11.0.23 was released September 30, 2017. Release 11.0.23 was scheduled to be released November 14, 2017. This has been delayed to November 14, 2017. To determine which version of Acrobat you have installed, check the version number associated with the system: The Acrobat software will display a version number within the system. On your system, look for the word “10.xx”, followed by a number and “13”. For example, XP 10.xx displays as XP, 11 .xx displays as 11, 12 .xx or 13 on your system. A serial number can provide evidence of your installation of Adobe Acrobat XI. A serial number is not proof of purchase. Acrobat XI is free. You do not have to do anything to use or install Acrobat XI. If you want to, you can disable Acrobat XI from your PC. Acrobat XI is currently not a supported application.