After starting Adobe Acrobat / Reader, from the menu bar or "≡"(menu button) in the upper left corner, please click "Help" -> "Check for Updates".
If the message “The program is in use.” appears while applying the patches, please close the Adobe Acrobat / Reader window and click “Retry”.
Updating Adobe Acrobat / Reader may take a long time, require a restart, or repeat the same procedure several times. Please repeat “Check for Updates” until no more updates are available.
Acrobat, included with Adobe Creative Cloud, can be updated from the Creative Cloud desktop app.
* If updating is not possible, please download the latest Adobe Acrobat / Reader from the page [1], [2] below.
[1] Download Adobe Acrobat Reader DC
[3] Products and technical support periods
[4] Adobe.com - Security Bulletins and Advisories