Problem Definition

The new Atlassian App Migration Platform (currently under development) will enable all Atlassian Marketplace Partners apps to build automated migration paths for their apps.

Suggested Solution

When a customer migrates from Confluence Server / Data Centre to Confluence Cloud using the Confluence Cloud Migration Assistant, the app migration platform will coordinate with Announcer for Confluence to automatically move Announcer for Confluence data associated.

Workaround
Please see link for instructions