Release 2.2.3 contains one important bug fix of general interest. Command setvcp --verify and API function ddca_set_non_table_vcp_value() were not performing verification. As a result of this fix, scripts and applications that hitherto always appeared to succeed when setting a feature value many now fail the operation.

The bulk of changes relate to bugs revealed by, and features needed by KDE PowerDevil. In particular, a new watch-mode, udev, uses UDEV notifications to detect display connection and disconnection. This is now the default watch mode when executing on Wayland. xevent remains the default watch mode when executing on X11.

Detailed information about the changes can be found in file CHANGELOG.md in the source tree, and on pages Notes for Recent ddcutil Releases and Shared Library Changes for Release 2.2.3 on the web site.

ddcutil 2.2.1 is primarily a bug fix release . The most significant changes are in how the shared library handles display connection and disconnection, and are needed by KDE Plasma PowerDevil

Shared library libddcutil is backwardly compatible with that in release 2.2.0. The SONAME is unchanged as libddcutil.so.5. The release library file is libddcutil.so.5.3.0

Detailed information about the changes can be found in file CHANGELOG.md in the source tree, and on pages Notes for Recent ddcutil Releases and Shared Library Changes for Release 2.2.1 on the web site.

ddcutil 2.2.0 is a major new release,

Most significantly, detecting and reporting display connection and disconnection has been reworked and enhanced, making libddcutil more useful to applications such as KDE PowerDevil, vdu_controls, and ddcutil-service.

Other enhancements include support for DisplayLink devices using driver evince. more consistent and extensive use of the system log, additional facilities for remote problem diagnosis, and changes in building, installation, and packaging. And, of course, there's a year's accumulation of bug fixes and minor enhancements.

Shared library libddcutil is backwardly compatible with that release 2.1.4. It contains some minor changes and additional API functions for display change detection. The SONAME is unchanged as libddcutil.so.5. The release library file is libddcutil.so.5.2.0

Detailed information about the changes can be found in file CHANGELOG.md in the source tree, and on pages ddcutil 2.2.0 Release Notes and Shared Library Changes for Release 2.2.0 on the web site.

Restore previously deprecated API function ddca_create_display_ref(), still in use. It is a synonym for ddca_get_display_ref(), whose name better reflects the role of the function. Its persistence in the Debian code base blocked ddcutil upgrade in that distribution.

Release 2.1.3 fixes a significant bug in libddcutil caused by overzealous checking of the DDCA_Display_Reference passed to various API functions. The display reference for displays reported as invalid (typically one for which the EDID can be read but DDC communication fails) was being rejected on API functions such as ddca_get_display_info(). In particular addresses ddcui issue 55 which reported a crash when one or more displays were invalid.

Detailed information about the changes can be found in file CHANGELOG.md, and on the ddcutil web site.

Release 2.1.2 fixes a critical bug in libddcutil that caused older versions of PowerDevil to repeatedly crash and restart.

Additionally, there are minor bug fixes and changes to accommodate the proprietary Nvidia video driver.

Detailed information about the changes can be found in file CHANGELOG.md, and on the ddcutil web site.

Highlights of release 2.1.0:

• Improved initialization performance
• Dynamic sleep improvement
• Cross-instance locking
• Shared library libddcutil is backwardly compatible with the one in ddcutil 2.0.0 The SONAME is unchanged as libddcutil.so.5. The release library file is libddcutil.5.1.0
• libddcutil watches for display connection and DPMS state changes and notifies clients.
• Improved control of initialization messages

Detailed information about the changes can be found in file CHANGELOG.md, and on the ddcutil web site.

This release provides a way to build and install only libddcutil.so.4, needed by client applications built against that older shared library. If configure option --enable-install-lib-only is specified, then only the shared library will be built and installed. Depending on their build process, some Linux distributions may find this useful. This is the only significant change from release 1.4.1.

ddcutil release 2.0.0 includes major changes in the areas of performance, usability, and reliability.

• Most users will find that command ddcutil just works "out of the box", without the need for manual configuration. Driver i2c-dev is loaded automatically in case it was not already built into the kernel. When executing on a system running systemd (i.e. on almost every current Linux distribution) the logged on user automatically has read-write access to the /dev/i2c devices associated with monitors, making excution as root or set up of group I2C unnecessary.

• The dynamic sleep algorithm was completely rewritten to use the minimal reliable sleep-multiplier value. Explicitly using option --sleep-multiplier to optimize performance should generally be unnecessary.

• The libddcutil API has been both extended and simplified. Some necessary changes broke full backward compatibility, requiring a SONAME bump from libddcutil.4 to libddcutil.5. Given the necessary SONAME bump, the opportunity was taken for a major API cleanup. Unneeded functions were removed, including many that were previously deprecated. Most client programs should build with minimal changes.

For details about the changes and bug fixes, see Release Notes and Shared Library Changes for Release 2.0. Changes are also summarized in source file CHANGELOG.md.

**Patch release 1.4.1 fixes a significant bug (#293) in release 1.4.0, which is withdrawn.

ddcutil release 1.4.1 contains some changes of general interest. More detailed documentation about changes and bug fixes can be found in source file CHANGELOG.md and on website page Release Notes.

Setting I2C device permissions has been simplified. Until now, the recommended way to give non-root users access to the I2C devices was to assign all /dev/i2c devices to group i2c, which has read/write permissions. Individual users would then be assigned to group i2c. This release simplifies permissions by adding a udev rule that uses the uaccess tag to give the logged on user read/write access to all /dev/i2c devices associated with video adapters. Installing package ddcutil installs file /usr/lib/udev/rules.d/60-ddcutil.rules.

To work around a bug in the Nvidia proprietary driver, use of the read()/write() interface of driver i2c-dev, which was removed in Release 1.3.0, has been re-enabled. This read()/write() interface of i2c-dev is used only with the Nvidia driver, and option *--force-slave-address can be used to address EBUSY errors that are possible with this interface. All other video drivers continue to use i2c-dev's ioctl() interface.

New configure options --enable-syslog and --disable-syslog control whether messages are written to the system log, which can pose problems if executing in a container. The default is --enable-syslog.

Command detect no longer issues the message "Is DDC/CI enabled in the monitor's on-screen display?", as this is rarely the cause of DDC/CI communication failures.

Prebuilt packages for several Linux distributions and machine architectures can be found in the usual locations.