pkg upgrade -fwill reinstall everything.
freebsd-update -r 12.0-RELEASE upgradeif you want to upgrade to 12.0-RELEASE.
Now base system has been updated. It is time to update all binary packages too. Simply run the following pkg command:
pkg-static install -f pkg
At this point, users of systems being upgraded from earlier FreeBSD releases will be prompted by freebsd-update(8) to rebuild all third-party applications (e.g., ports installed from the ports tree) due to updates in system libraries.