Our stake recently changed the ward boundaries which put me in a new ward. My donations updated to the new ward but my calendar still shows my old ward. I can't find a way to change which ward calendar I have access to.
Odd as it may seem, many have found that simply going to the subscription screen of the Calendar causes something in the system to recognize your new ward and reset the Calendar for you. It seems to work for those who move, and others have had success after a boundary change such as yours.