Coming from 1.x

No upgrade path

Droost 2.x is a re-architecture, not an update. 1.x is not supported as an upgrade source and 2.x ships no upgrade hooks for it. The safe route is a clean cut: uninstall 1.x completely, then install 2.x as a new module.

What changed

Seven 1.x modules merged into core: droost_search, droost_wiki, droost_brain, droost_profiler, droost_knowledge, droost_help, droost_playbook.
The install became two paths (droost:install for the toolset, droost:workflow:install for the pipeline) and the five-command runbook, the setup wizard and the restart step are gone.
The workflow became the default path, with the require_run wall on when the pipeline is installed.
Drupal 10 support was measured, found to have never worked, and dropped. The floor is ^11.1 || ^12.

The clean cut

bash

# Still on 1.x: uninstall every droost module while its code exists.
drush pm:uninstall droost      # and any droost_* submodule you enabled
composer remove drupal/droost

# Then install 2.x as a new module.
composer require --dev 'drupal/droost:^2.0@alpha' 'drupal/mcp_server:^2.0@alpha'
drush en droost -y && drush droost:install

Uninstalling first is required, not advised. A merged module left in core.extension with no directory on disk breaks bootstrap before any repair hook could run.

What you lose, and what survives

The brain and search indexes regenerate from your code: drush droost:brain:build, drush droost:search:index. Both run as part of droost:install.
A wiki bundle is plain files on disk and survives. 2.x defaults its location to droost/wiki; if yours lived at the old docs/wiki default, point droost.wiki.settings.path at it, or move the bundle.
Editor wiring is rewritten by drush en droost, so any hand-edits to .mcp.json or AGENTS.md made for 1.x should be reviewed rather than carried.

If you are on alpha1 or alpha2

2.0.0-alpha2 cannot be installed: it pins an engine version whose next patch release broke an interface, so a fresh alpha2 install fatals on bootstrap while the front page keeps serving from cache. Update to alpha3 or later from Composer alone, no bootstrap needed:

bash

composer require --dev 'drupal/droost:^2.0@alpha' -W
drush cr

Alpha1 and alpha2 also shipped with rich-text editing broken on every install through droost_examples. Alpha3 fixes it; on the older releases drush pm:uninstall droost_examples restores editing.