Campaign issues
With campaign issues, you can choose your target audience, default email settings, design and content for your email campaign once and name it, for example My Monthly Campaign. Then every time you want to send an email campaign, for example January Email Campaign, you will end up in the last sent state of your campaign. From there you will be able to modify only the information you want for the new campaign, without starting from scratch. Delivering this increment of your campaign is what an issue is.
Because an issue contains everything required to be sent for the current state of the campaign, the issue class is the campaign class.
Campaign model class
The Campaign class has a property - RootCampaign that keeps the hierarchical structure of an issue (which is actually a campaign) related to a specific campaign.
Following is a sample of the RootCampaign property of the Campaign class: