A.1 Implement a Login button tapping to which the Login screen (for iPhone) or floating window (for iPad) is shown where user enters login/password and can tap Login or Cancel button, also switch button is provided to allow user to store entered credentials for auto-login purpose. Also Login screen contains Register link taping which the default system browser is launched opened predefined URL.
A.2 Implement verification of entered credentials (and device unique ID?) using server API and store them (if was requested by user) if credentials are valid, otherwise show alert. In case of successful verification the session key is stored to be used in other APIs.
A.3 Update and retest all existing communications to support work with session
B.1 Implement custom view to show ads banner (1-size for iPhone and 2-size for iPad), handle taps in it and open link in default system browser
B.2 Implement fetching and iterating of ads (configuration XML + images) using server API
C. Embedding an offline list of word suggestions in the app (so as to make the searches faster and lest sluggish)