Termination of apartment lease; landlord moved without providing a new address

Basically, the termination will definitely be valid. The problem is, you cannot prove that you posted the letter. A registered letter would have been a much better option here. I would advise you to call a lawyer or maybe speak directly to the landlord. He will also be aware of his mistake that he did not inform you. Surely, an agreement can be reached. Good luck!

- No legal advice -

Basically, the termination will definitely be valid.

Uh, what do you mean by "valid"? And why "definitely"? Please let us in on your thoughts. Where exactly is your post supposed to lead?

I would especially be interested in how your suggestion ".. or maybe just speak directly to the landlord" is supposed to be feasible if they have moved away without forwarding address.

Furthermore, I would be interested in how the "agreement" is supposed to look if the termination is supposed to be "definitely valid." Then an agreement would be irrelevant. Or am I missing something?

Overall, probably a well-intentioned but then not so helpful post.

I would ask the city. After all, they have to know where he lives (registration change). They will not be allowed to give you the address, but they might be able to deliver the termination notice if you explain the situation to them.

But of course they will provide the address! You simply submit a proper request for information from the registration office, which costs a few euros. No reasonable person would want to doubt the entitlement to information, since the requester ultimately has a contractual relationship with the "person sought." It is possible that you have to prove this, so I would take the rental contract with you.