Please follow the instructions for getting DisplayCAL via Zero Install, then continue below.
Zero Install will default to the latest stable version of DisplayCAL. To use the latest development snapshot instead, under Windows/Linux refer to “Manually updating or switching between software versions” to bring up the version selection window, and set the preferred stability to “testing”.
Under Mac OS X, use the “0install Launcher” application from the DisplayCAL-0install.dmg disk image, then click “Settings” and place a check in the “Help test new versions” checkbox.
Note that the snapshot is considered unstable and may contain bugs. I encourage you to report any bugs you find. In case the bug is easily reproducible, I can release an updated snapshot very quickly.