From the Edit menu, select Preferences, then click on the Online Sync tab (or from the Business group on the main toolbar, click 
Preferences, then 
My Account). View
My Account Credentials: The email address and password on your Main Street account online, need to match what is stored in your Boulevard program to ensure you continue to receive current product updates, install available software releases, and sync to the Avenue app. See Updating Your Email Address & Password for more information.
Outgoing Email Settings: Choose whether to link your email address inside Boulevard or launch a Desktop client such as Outlook, Windows Mail, Thunderbird, etc.
Avenue Mobile Sync: This section is only applicable if you have a current subscription to the Avenue app. Choose which information, and how much is being transferred to the app when a sync is performed. Also, an additional option to be prompted to sync to the Avenue app when exiting Boulevard.