If I turn off auto renew before expiry of a in-app subscription, ios says it will send me DID_CHANGE_RENEWAL_STATUS, so after that when the actual expire time comes will ios again notify me? As I am unable to turnoff auto renew on sandbox I am not sure what will actually happen
Short answer - no. Apple will not notify you when actual expires date comes. However, you can extract expires_date from other notifications and from receipt itself and remember it.