I have been using the API for a while and now I notice that some internal rules seem to have changed.
I am used to perform Subscribers.GetIsSubscribed to find out, wether an e-mail address is subscribed in a certain list. When the address existst, but is still unconfirmed, I get "False" back. I remember that it has been "True" some weeks/months ago. Did that change or am I wrong?
In general, is there any possibility to get informed about any changes in the API? A mailinglist or blog or something?
It's possible you're mistaken with regard to Subscribers.GetIsSubscribed. It returns true only if a subscriber is in the active state (ie, would receive a campaign sent to that list), and unconfirmed subscribers are definitely inactive. That behaviour should not have changed.
In general, if we do make changes to the API they would be publicised on the campaign monitor blog, but we make sure to maintain backwards compatibility. Old code would continue to work without any changes.