Case Study · TYPO3 Migration · Multi-Concept

// case_007 · typo3_major_migration v10 zu v12. Drei Konzept-Wechsel dazu. Und kein Big Bang.

TYPO3 v10 → v12, PHP 7.4 → 8.3, Masks to ContentBlocks, Gridelements to b13/container, legacy fork modernized. A major migration in four phases, with no downtime, featuring a reproducible migration path.

v10 → v12
TYPO3 versions
4
Major PHP version updates
3
Custom extensions migrated
0
Big Bang risk

Background

TYPO3 v10 + Mask + Gridelements + Legacy-Fork.

Medium-sized mechanical engineering company. CMS has been stable for years. v10 is being phased out, and there is a significant backlog of work.

What Big Bang migrations mean

v10 → v12 plus a change in approach = 6+ weeks of downtime, high risk. No one dares to do it.

What we did

4-phase plan with live testing after each phase. No wasted hours, no downtime.

Three Ways

Big Bang, Re-Build oder Phased Migration.

Option A

Big Bang

Migrate everything at once.

Risk very high
Time 6–8 Where Things Have Come to a Standstill
Costs high
Episode Live problems guaranteed
Option B

Rebuild (new stack)

Build it from scratch using a modern framework.

Risk a great loss
Time 6+ months
Costs very high
Episode Loss of knowledge
Option C

4-phase migration

In stages: first the core, then the individual concepts.

Risk controlled
Time 12 Where phased
Costs medium
Episode testable per phase

4 phases

Migrations-Pfad ohne Big Bang.

Phase 01
TYPO3 Core v10 → v11 → v12

Composer update, schema migration, tests. PHP 7.4 → 8.3.

Where 1–3
Phase 02
Mask → Content Blocks

24 Mask elements ported to ContentBlocks. Field mapping, data migration.

Where 4–6
Phase 03
Grid elements → b13/container

Layout container updated. Content structure retained.

Where 7–9
Phase 04
Refactor Custom Extensions

3 custom extensions on the v12 API. Testing, deployment, live.

Where 10–12

Tools

Migrations-Stack.

Migration Tool

typo3/cms-install

  • upgrade:run
  • extension:setup
Content Blocks

friendsoftypo3

  • v1.1 stable
  • Mask-Migration manuell
CI/Deployment

Deployer

  • Phased Rollout
  • Rollback-fähig

Voice

From the mandate.

We knew we had to migrate. We didn't know how to do it without a 6-week downtime. Phased migration with live testing at each stage was the lightbulb moment.

Direktkunde · Maschinenbau Joint supervision of the March Advertising Agency
Direct

Three Lessons from Migration.

01

Phase Migration > Big Bang. Always.

02

Concept changes are distinct phases, not bonuses.

03

Live testing at each stage prevents lengthy rollback processes.

Frequently Asked Questions

Planning a major migration? We’ll handle it in phases—without any downtime.

Free initial consultation; migration plan at a fixed price.

Request a migration plan Similar cases

// further reading

Related articles from our blog

TYPO3 v14 LTS: What You Need to Know Before the Upgrade on April 21

TYPO3 v14.3 will be released as a Long-Term Support (LTS) version on April 21, 2026. Nine days later, free support for TYPO3 v12 will end. These are two dates that are relevant for every company with a TYPO3 website. Here’s what you need to do now. What happens on April 21? TYPO3 v14.3 LTS will be officially released on April 21, 2026, at […]

Read more

TYPO3 Update Costs in 2026: What an Upgrade to v13 LTS Really Costs

TYPO3 v13.4 LTS has been the standard since October 2024 — v10 has been out of free support since April 2023, and v11 since October 2024. Anyone still running v10 or v11 without ELTS is operating without security patches. Depending on the number of extensions installed, a major update can cost anywhere from four to five figures. We’ll show you what drives the cost and how to recognize a realistic quote.

Read more

TYPO3 or WordPress 2026: Which CMS Is Right for Your Business?

The choice between TYPO3 and WordPress is a decision that affects years, not months—switching systems later on costs time, money, and search rankings. TYPO3 excels at complex multilingual projects and enterprise-level content management, while WordPress shines in terms of speed and cost-effective implementation. We’ll show you when each option is the right fit—and when neither is the best choice.

Read more