Hello Richard,
hmm, strange that both behave different. To be honest I do not recall that
I have seen an update dialog without the question for the upgrade key.
In general there is not much what you can harm at this point.
The software upgrade would stop without executing after a while when it finds a wrong release key.
If you already have a x6 running you should also be able to just leave the release key
field empty, but on the other hand it does not harm neither to copy paste the release
key as you suggested yourself.
Btw, log in via ssh/console before you start the upgrade, then you can see som status info during
the upgrade process in the terminal.
If your question is answered, please mark the question as answered and anyhow vote the answer, thx! :-)