Make a full wallet backup right away and store it somewhere safe TOGETHER with the passphrase ..
First, I had a the older wallet and got the password and passphrase down on paper. Does the passphrase change when upgraded to 2.0? Or is there another passphrase generated?
Thanks
The passphrase does not change. It's the same.
I do use different passphrases for 0.9 and 2.0.
I'll be more specific:
To create a new wallet under 2.0 you can use any passphrase you like. But during the process of importing 0.9 funds into 2.0 you'll need to use the 0.9 passphrase.
So the whole process goes like this:
(1) First you create a new wallet in 2.0 and create any passphrase you like.
(2) Then you do the import of 0.9 funds and for that you'll need to use the 0.9 passphrase.
(3) After a successful import the 0.9 passphrase is not needed any more. From now on, the only passphrase needed is the one you created in (1)