On 2025-04-29, Codex v2.0.0-rc.1 will be released and merged into MediaWiki core. Once that happens, we can start testing on beta wikis.

Testing plan

Once the core patch is merged, we can begin testing on beta wikis:

• Beta English Wikipedia: https://en.wikipedia.beta.wmflabs.org/wiki/Main_Page
• Beta Meta-Wiki: https://meta.wikimedia.beta.wmflabs.org/wiki/Main_Page

We'll test the following:

• Test in Vector 2022, Vector legacy, MinervaNeue, and Monobook
• Ensure the Vector 22 header and sidebars do not scale with text size
• Test login and create account forms
• Test a messagebox in content (may need to add a CSS-only message to page content)
• Test Special:ContentTranslation
• Test Special:Block with ?usecodex=1 (muiltiblocks)
• Test Special:MediaSearch
• Test Special:Nearby
• Test Special:NewPagesFeed
• Test Special:Preferences (not a Codex UI; ensure nothing has changed)

Anticipated findings

Status quo:

• There should be no Less compilation errors; styles should load normally.
• Interfaces that do not use the Codex toolkit should be unchanged.
• Page titles and article text should be unchanged.
• In Vector 2022...
  • The header and sidebars should not scale with text size. Only the content region should scale.
  • The QuickSurveys UI and Message components within content should not scale with text size.

Changes:

• Codex components and interfaces that use Codex design tokens may look slightly different but any changes should be either negligible or improvements. Some more noticeable visual changes include:
  • Dialog titles have increased in size.
  • Spacing between binary inputs within groups has reduced.
  • Padding in non-inline Messages has reduced.
• In MonoBook...
  • Codex interfaces (e.g. the login form, the Codex version of Special:Block) will use the small font mode and will therefore be based at a 0.875rem/14px font size. This means they will be ~10% larger than the existing size (based at 12.7px).

Acceptance criteria

• Everything in the list above has been tested on at least one of the beta wikis
• Any findings are discussed within the team