When you use the pkg update command with no package FMRI or pattern specified, or with an asterisk character (*) as the pattern, all installed packages that have updates available are updated to the newest version allowed by the constraints imposed on the system by installed package dependencies and publisher configuration.
If you do not want to update to the newest version allowed, see the options discussed in Updating to a Version Older Than the Newest Version Allowed.
No new packages are installed unless they are new dependencies required by an updated installed package.
Installed packages are updated only if a configured publisher provides an updated version that fits the constraints of the image being updated. Constraints are imposed by package dependencies and by configuration such as the following that you can control as described in Configuring Installed Images:
Packages locked at a particular version
Facets and variants set in the image
Package signing properties configured
Publisher search order and stickiness
If any required package cannot be installed, no packages are updated or installed. See Troubleshooting Package Installation and Update.
Upgrading your system means updating a bootable image. A system can have multiple bootable images, as noted in Images and Boot Environments.
If non-global zones are installed in the current image, these zones are also updated. See Working with Non-Global Zones.
Updating requires increased privileges. See Installation Privileges for more information.
For a complete list of all options for the pkg update command, see the pkg(1) man page.