Application evolution in a  distributed environment creates some significant challenges.  The agent-centric approach used through Holochain's design and implementation gives us some some useful tools to meet those challenges.

A core capacity built into Holochain is the ability to migrate an application, that is to mark it is as closed and point to the new application and identity that activity has moved to for this agent.

There are at least three usecases we have in mind for migration:

• transient app management: tracking data across short-lived apps (e.g. a chat room channel)
• the "traditional" app migration: massage the shape of data to align with code changes
• "in situ" data management: janitorial tasks for chains (e.g. log rotation)

Here's an article about our progress using migration.