Support safe rollback/downgrade to previous versions

Feature summary

No response

What problem are you trying to solve?

When a new Copilot App release introduces regressions, users need a reliable way to roll back to a previous version. For e.g. the last few versions (1.1.14 - 1.1.17) introduced a lot of blocking regressions that resulted in the app being unusable.

Currently, downgrading on Windows can leave the older version unable to open the existing application data. After installing an older version, the app reports:

Your data was created by a newer version of this app than the one you have installed (version 1.1.14).

This effectively prevents a safe rollback and can force users to choose between using a problematic release or potentially losing their local application state.

Proposed solution

Provide a supported, safe rollback mechanism for the Copilot App.

Before upgrading, the app should preserve a version-compatible backup/snapshot of the user's application data. If a user subsequently installs a previous version, the app should be able to restore the data that existed before the upgrade.

Ideally, this would be exposed as a simple "Rollback to previous version" or "Restore previous version data" workflow.

At minimum, the app should provide a documented and supported way to downgrade without losing conversations, settings, and other locally stored application state.

The important requirement is that an application update should not make the previous version unusable simply because the newer version migrated its data.

Workflow impact

This would primarily benefit users who encounter regressions after a Copilot App update.

Desktop applications need a reliable recovery path when an update causes unexpected problems. Without one, users may be unable to return to a previously working version without manually manipulating application data, potentially losing local state in the process.

A safe rollback mechanism would make updates substantially less risky while allowing users to recover quickly from regressions and continue working with a known-good version.

Installation context

Windows

Additional context

I'm currently seeing this when attempting to downgrade on Windows:

Your data was created by a newer version of this app than the one you have installed (version 1.1.14).

Please update to the latest version to continue. Your data has not been modified.

The newer version appears to have migrated the local application data in a way that the older version cannot consume. If it is safe to rollback this message seems to indicate otherwise. I have too many sessions, and lot of settings/configurations to risk losing them.

Screenshot of the error dialog is attached.

No source files, tests, or entry points are identified in the issue. Start by tracing the Windows application's data migration and version-compatibility handling, then determine how upgrade snapshots could support restoring conversations, settings, and other local state. Done means a documented or built-in rollback path lets a previous version open restored data safely.