I want to add a new mail address to launchpad. I was able to add a new address and I confirmed the address, but I can't use it for example for mailing lists. I can't set it as contact address.
If you log in to your old account and click on the yellow icon next to where it says Email on your userpage, you can change your email address there and set one as default.
From this answer:
You can change your email address for notifications but beware that the login address will still be the one used for registering so don't forget it.