TYPO3 Project Upgrade Skill

Claude Code skill for upgrading deployed TYPO3 project instances across major LTS versions.

Scope

This skill covers project-level upgrades — the deployed website, its configuration, templates, infrastructure, and database. For upgrading extension code to new TYPO3 APIs, use typo3-extension-upgrade.

What It Covers

• sys_template → Site Sets: Migrating TypoScript constants/config to TYPO3 v13+ site set YAML files
• SCSS Variable Injection: Using Bootstrap Package's ScssParser to override BS5 variables without CSS hacks
• Bootstrap 4 → 5 Migration: color-contrast, link-decoration, frame custom properties, navbar changes
• Bootstrap Package v12→v16: Navigation split link/button, dropdown-hover removal, position:sticky, known bugs
• Infrastructure: ImageMagick in Docker, GFX configuration, processed file regeneration
• Database Cleanup: sys_template deletion, FlexForm updates, stale record cleanup
• Review Methodology: Structural comparison via curl, difference categorization, visual verification

Installation

Claude Code (marketplace)

claude mcp add typo3-project-upgrade -- npx @anthropic-ai/claude-code-marketplace typo3-project-upgrade

Manual

Copy skills/typo3-project-upgrade/SKILL.md to your Claude Code skills directory.

Assessment Checkpoints

This skill includes checkpoints.yaml for the extension-assessment framework. Run against a TYPO3 project to verify upgrade completeness:

• 9 mechanical checks: Site set existence, sys_template cleanup, ImageMagick, GFX config, SCSS usage
• 4 LLM reviews: Site set completeness, BS4→BS5 migration, navigation, infrastructure

Based On

Real-world migration of typo3-demo.netresearch.de from TYPO3 v11 (Bootstrap Package v12) to TYPO3 v14 (Bootstrap Package v16). Upstream contributions:

• benjaminkott/bootstrap_package#1618 — Sticky header JS fix
• benjaminkott/bootstrap_package#1619 — Sticky header CSS root cause fix

License

• Code: MIT
• Content: CC BY-SA 4.0

Copyright (c) 2026 Netresearch DTT GmbH