Yes. The 15.6.5 update is cumulative. It contains all previous patches from 15.1, 15.2, 15.3, 15.4, and 15.5.
Adobe officially ended support for Acrobat DC 2015 (Classic) on April 7, 2020 . This means there are no new security updates, and the software may be vulnerable to exploits. Additionally, Adobe has removed the official public download links for these older installers from their main site.
Because this version is discontinued, the standard in-app updater may no longer function. You can still find manual update files through these methods: adobe acrobat pro dc 2015 update download
Open the mounted volume and double-click the installer bundle.
This track provides service innovations and new features alongside security and bug fixes. It is primarily used for subscription-based licenses. Adobe officially ended support for Acrobat DC 2015
If you have Adobe Creative Cloud installed on your computer, you can also update Adobe Acrobat Pro DC 2015 through the Creative Cloud app.
: Temporarily disable your third-party antivirus shields, close all open web browsers, and run the update again. Turn your antivirus back on immediately after the installation finishes. Important Notice on Adobe End of Support Because this version is discontinued, the standard in-app
The final updates for the 2015 “Classic” track were around version (mid-2016). Later updates (15.0xx) require a newer base installer.
This is a guide on how to handle updates for (specifically the "Classic" or Continuous track release from that year).
Navigate to the official Adobe Acrobat Release Notes website.