Yeah, that guide is a bit old.
But that guide is NOT about port forwarding, which your question and topic was about.
That guide is about ESSENTIAL BitComet settings and they indeed have stayed the same, for very many versions.
Namely:
choosing a port number above 49152 so that you are sure that no other application has registered for that port;
making sure that your upload speed is capped to 80% of your TESTED upload speed;
not running too many tasks at once, in order to NOT spread your upload bandwidth too thin and then appear to any other peer as an undesirable trading partner, which would cause your download speeds to drop dramatically.
Now, you would have to watch out for these, whether you use v.0.70 or v.1.23, just the same. The places where you can do these changes aren’t that hard to find, in any of the versions.
There are more guides which are a bit outdated, as far as images go, but they will be updated as time is found, seeing that all the staff members of this forum are unpaid volunteers which donate some of their spare time, in order to keep the forums going.
Updating a guide, may require a little bit of work and time, and seeing that is still serves its purpose, it went at the bottom of the priority queue.
But when anybody of the staff finds that time, I guess it will be done.