Transferring a license documentation for v8.1?

In the v7.9 documentation there is Transferring a license

In this question it says that the equivalent link for v8.0 is

But that link is now dead. And I can’t find the equivalent information anywhere for v8.1

So what is the equivalent link for v8.1?

It looks like the contents of the page got folded into a single larger page. The technique is still exactly the same as described for 7.9; unactivate the first gateway, then activate the same key on the new gateway. It’s mentioned in the unactivation instructions:
After the unactivation, you just follow the standard activation flow:

Given that there has been an explicit “transfer” topic in previous documentation versions, it might make sense to include some similar wording in the 8.0+ docs so that a search at least lands you on that new page.