Upgrade, roll back, or remove NOW

Goal

Change versions without creating a host/guest contract mismatch or forgetting the optional resident component.

Update the PowerPC application

1. Install or build the modern host together with the PowerPC artifact it should publish.
2. Connect the PowerPC guest and open its Connection page.
3. Read the Application row under Updates from the other Mac. The row compares both release version and exact build identity, so a different scratch build of the same version is still shown.
4. Choose Install App. Development artifacts currently have a SHA-256 integrity check but no release signature; confirm the unsigned-build warning only if this is the host and build you intended to trust.
5. Let the transfer complete. The guest verifies the exact MacBinary stream, exchanges the new application with the running copy, quits cleanly, and asks Process Manager to launch the replacement. The old application bytes remain beside it as New Old World Update for rollback.
6. After reconnection, verify the exact build shown by Connections and exercise one capability. A completed download alone is not behavioral verification.

Update the NOW Extension

1. In the same Connection page, read the Extension row. If the active Extension version differs from the application expectation, NOW shows a warning even before a replacement is installed.
2. Choose Install Extension and, for a development build, confirm the unsigned-build warning.
3. After the guest reports installation, restart the classic Mac. An INIT is not active until boot; do not judge resident behavior before restarting.
4. Reopen NOW and confirm that the mismatch warning is gone and the resident capabilities you use are available.

The previous resident bytes are retained under the staging name and changed to a non-INIT Finder type, so they cannot load alongside the replacement.

Manual fallback and rollback

The in-app updater is host-owned publication, not internet update discovery. If the host has no validated update sidecar, Connections honestly says there is no update; use the setup portal or manual MacBinary deployment instead.

To roll back, quit NOW, remove the replacement, and restore the retained application or Extension under its canonical name and Finder type. Restart after any Extension rollback. When the wire contract revision changes, restore the host and guest as one rollback set rather than mixing revisions.

To remove NOW, delete the host and guest applications; also remove NOW Extension from the System Folder and restart if it was installed.

Expected result

The guest reports the exact host-published build, verifies it before replacing anything, and either installs it or retains a precise refusal. Extension activation always remains pending until restart.

Recovery

If the classic Mac cannot boot after an extension change, start with Extensions disabled, remove NOW Extension, and return to the non-resident product shape.

If application relaunch does not complete, launch the canonical New Old World copy manually. The exchanged rollback file remains in the same folder.