There is an unsubscribeUrl attribute on editor element in EPiServerMail.config, you could customize that if you have a custom version of the unsubscribe page.
I've found the 'unsubscribeUrl'-attribute along with some parameters:
What I wanted to know is if there's some way to add ones own custom parameters?
Can you give an example of what you'd want to include in the query string?
I've been thinking about passing along a page ID:
where XYZ is a page ID.
Then we would be able to have customized unsubscribe pages based on a template instead of a single, generic unsubscribe page.
However I don't know if it's possible to achieve the above mentioned, or if it's even a good idea.
If you just want a static id there, it should be no problem. If you want the id to be replaced by EPiMail the value it should be replaced with would have to be made available somehow.
That essentially means it would have to be one of the recipient attributes (values that can be inserted at placeholders in the mail text), but those are specified per recipient. It would be possible but it may not be the right way to go.
Another possibility, which sounds to me like it may be preferrable (if possible), would be to just have a completely custom link with the required parameters in the querystring in the templates used for the different types of newsletters.
Is it possible to specify custom parameters in the unsubscribe URL? I have "rid" and "mid" but would like to add some more.
We're running EPiServer Mail 4.4.343.20.