Updating from 11.3-stable to 12.1-stable?

[Per Hedeland]

On 2020-04-28 00:00, Steve O'Hara-Smith wrote:
> On Mon, 27 Apr 2020 23:41:50 +0200
> Polytropon <freebsd at edvax.de> wrote:
>
>> from scratch, add your OS modifications, then install your
>> "top level ports" (the things you're intending to use), and
>> all required dependencies will be resolved automatically as
>> they are needed.
>
> 	Run pkg leaf on the existing system to get a first cut of the list
> of packages to install.

Hm, that sounds like it could be quite useful for the way I typically
do upgrades, but

$ pkg leaf
pkg: unknown command: leaf

For more information on available commands and options see 'pkg help'.
$

- and I'm afraid I can't spot a likely candidate for a typo in pkg(8).

Please help!:-)

Thanks

--Per Hedeland