Change Layout for security/practicability

[StephWo]

The recipients Address is almost too high on the page for normal DIN Lang envelopes. Lazy Postmen could dimiss the letter if Address is not fully readable.
The senders address is not visible at all.

Also, depending on the thickness of the envelope, the QR-Code might shine through it so that it could be read without opening the letter. Maybe it could sit somewhere else on the page? Swap with the "Kontakt:"-Section?
Then the QR-Code would be, if folded normally, under 2 sheets of paper.