Migrating from Sierra on one box to High Sierra on another

[Dave Horsfall]

I don't have web access right now, hence the list...

My ancient Sierra MacBook failed (graphics board which is no longer 
available) but I have been offered a more recent second-hand one for a 
reasonable price, and it will run High Sierra (I don't want Mojave just 
yet).

What's the procedure to update all the existing ports i.e. is there such a 
thing as "port upgrade all" to do "the right thing"?  I have the old 
system drive available (external USB - long story) and can slurp the 
appropriate files over (I don't like restoring using Time Machine, and the 
Capsule may not be up to date anyway, as I was working when the video 
disappeared).

I know that I have to recompile my own stuff.

Anything else that I should know about?  I like to be forewarned, and 
remember that I don't have web access right now.

Thanks.

-- Dave