I used the same seed as before and it worked. haven't send out anything yet, but will test that in a few minutes
They have strongly advised against using the same seed "Do I really need to generate a new seed? Yes. This is a safety precaution that we have taken to ensure that everything happens smoothly." ( source
https://blog.iota.org/new-gui-transition-phase-explained-b536ed80f412 )
and on Slack Dominik Schiener repeated that it is mandatory to use a new seed for security reasons.