Support for Adobe Acrobat 11.x and Adobe Reader 11.x ended in October 2017.
Adobes end of support announcement explains that they will no longer provide technical support or product and security updates for the 11.x versions of Adobe Acrobat and Reader. You may continue to use these Adobe programs but there will no longer be technical support or updates available for version 11.x of the programs.
JMK recommends that you update to the latest version of Adobe Acrobat DC and Adobe Acrobat Reader DC. Installing the latest updates will ensure your access to program enhancements and security updates.