You can use the pkg update command to downgrade as well as upgrade packages. To downgrade a package, specify the package FMRI with a version older than the version that is currently installed. See Fault Management Resource Identifiers for a description of a package FMRI. Use the pkg list command to see which version of the package is installed and which versions are available from configured publishers.
Any preserved configuration files that are part of packages to be downgraded are installed or renamed according to the value of the preserve attribute on the file and whether the file has changed. For information about how files are preserved during package downgrades, see the preserve attribute in the “File Actions” section of the pkg(5) man page.
See Installing a New Package for information about using the -g option.