Could someone of you please help me with a small problem?

I have been using an older version of the Agama app for several months now.
So far without problems. Now I would like to update to the latest version.
However, this is only possible through a new installation. So far, I only have my seed, no backup.
Since there has been an address change by claiming interests, the seed is no longer enough, right?
I read that with my seed I would only get the original address, which is empty now.

So what do I have to do to get my coins into the new app?

Thanks already for your help.

Greez Sam