I’m guessing I know the answer, but before throwing away an expensive ticket...
I just noticed that ZVV multi ride all zone tickets now have an expiry date. (Shows how infrequently I travel.) Mine will expire soon, before I have a chance to use them.
Is it possible to have unused multi ride tickets extended? Or are these now just book marks?
I wouldn't recommend using it if it'd already expired (but I'm sure that's not what you intended, anyway).
To your question: I once had exactly your situation. I went into a sales point and they took in the old multi-ticket and cancelled it, and reissued me with a new one. As mine was old, they used that old tarif for the caluclation and I had to pay in the difference, but was glad to do so. However, this was many years ago, and I don't know whether it'd still work. Computer might say "no". It's surely worth trying, I'd think. Take your ID along, just in case, possibly also SwissCard, if you have one.
Though it seems only for monthly and annual and not multi-use ones. I think until a year ago or so they did not print any expiry date. At least I used to have multi use tickets without any expiry date and was surprised to see the new practice.
As far as I remember, an expiry date first appeared on multiple journey tickets about 5 years ago. First the validity was longer, like 3 years, I think, but recently they've reduced it to only 1 year.
Went to the station in person. Exchange for new multi ride tickets no problem. The nice gentleman even gave me a choice of new tickets good for another year or refund.
Surprised - and delighted - at how easy this was. And very happy not to throw a couple hundred Chuffs out the window.