Release 2.2.7 contains extensive changes to libddcutil, particularly for detecting display connection and disconnection. Several bugs triggered by KDE PowerDevil have been fixed. There is no urgency to update for users only of command line ddcutil. On the other hand, users of KDE Plasma will want to update as soon as possible.
In particular, changes have been made to address the transient EACCES errors that some users experience, and to document the system state when they occur. Unfortnately, I am not able to reproduce the problem, so I am not sure that the problem has actually been solved. Reports from users who have had the problem. as to whether or not it has been fixed, will be most helpful.
The most complete documentation regarding the changes in this release are to be found in tile CHANGELOG.md in the source tree.