While it is possible to install SVR4 packages directly on an Oracle Solaris 11 system, you should create IPS packages instead. Installing SVR4 packages is an interim solution.
Apart from the legacy action described in Legacy Actions, no links exist between the two packaging systems, and SVR4 and IPS packages do not reference package metadata from each other.
IPS has commands such as pkg verify that can determine whether packaged content has been installed correctly. However, errors can result if another packaging system legitimately installs packages or runs install scripts that modify directories or files installed by IPS packages.
The IPS pkg fix and pkg revert commands can overwrite files delivered by SVR4 packages as well as by IPS packages, potentially causing the packaged applications to malfunction.
Commands such as pkg install, which normally check for duplicate actions and common attributes on reference-counted actions, might fail to detect potential errors when files from a different packaging system conflict.
With these potential errors in mind, and given the comprehensive package development tool chain in IPS, developing IPS packages instead of SVR4 packages is recommended for Oracle Solaris 11.