Do I need to have my entire software rewritten?

No. A complete rewrite ("Big Bang") often fails. We recommend an iterative approach (e.g., Strangler Pattern). We stabilize the core and gradually migrate individual modules (e.g., billing, user auth) to new services.

My software runs on PHP 5.6 / 7.0. Is that still secure?

No, these versions are "End of Life" (EOL) and no longer receive security updates. We can first package the application in protected Docker containers to mitigate the immediate risk, then plan the upgrade to PHP 8.x.

Can you refactor spaghetti code?

Yes. We analyze the code, perform static code analysis (SonarQube), and gradually introduce typing (e.g., PHP Type Hints, TypeScript) and tests to make the code readable and maintainable.

How do you prevent downtime during migration?

We use "Blue/Green Deployments" and load balancers. The old and new versions run in parallel. We gradually switch traffic over. If something goes wrong, we immediately switch back (rollback).

What if our original developers are no longer available?

That's the norm. We perform reverse engineering, analyze code without documentation, and create up-to-date architecture documentation. This makes the knowledge accessible again - independent of any individuals.

What does "containerization" of my old app give me?

It decouples your software from the server. Old software often needs old libraries (libssl, glibc) that are missing on modern servers. In a container, we include these dependencies. Your 10-year-old app runs safely on a brand-new high-speed server.

We still use SVN or have no version control at all. Can you help?

Yes. The first step is often introducing Git. We import your code, set up repositories (GitLab/GitHub), and define branching strategies so multiple developers can work safely in parallel again.

Do you also handle database migration?

Yes. Data is gold. We write scripts that extract data from old schemas, clean it (fix encoding errors, normalization), and transfer it to modern databases (PostgreSQL).

What happens to our existing integrations and interfaces?

We document all existing APIs and integrations during the audit. During migration, we ensure all interfaces (ERP, CRM, payment providers) continue to work. Often we even improve them with clean REST/GraphQL APIs.

Our interface looks like Windows 95. Can you modernize that?

Yes. We can keep the backend (logic) but build a modern API in front of it. We then add a contemporary frontend with React or Vue.js. The software feels new to users without rewriting the core ("Headless" approach).

Do you use microservices or monoliths?

We're not dogmatic. For many SMBs, a well-structured Modular Monolith is better than 50 complex microservices. We choose the architecture that fits your team size.

How does a modernization project start?

With a Code & Infrastructure Audit. We examine the source code and servers, identify the biggest risks ("low-hanging fruit"), and create a modernization roadmap.

Can you support our internal development team?

Absolutely. We often work as an "expert team" handling the difficult architectural changes and introducing CI/CD, while your team continues daily operations and learns from us ("enablement").

What does modernization cost?

It's cheaper than a complete rebuild, but still an investment. Since we work incrementally, you have monthly predictability instead of a massive upfront investment.

How long does a typical modernization take?

It depends on scope. Containerization (Lift & Shift) can be done in a few weeks. A complete Strangler Fig migration can take 6-18 months - but you'll see results after the first sprint.

Do you also handle maintenance of the old app while the new one is being built?

Yes. We take over operations and bug fixing of the legacy application (maintenance) so your team can focus. This allows us to modernize in parallel without affecting day-to-day business.

Legacy Software Modernization

We rescue your legacy software. Modernization, refactoring, and cloud migration for outdated applications - without disrupting ongoing operations.

Lift & Shift
Strangler Fig
DB Migration
CI/CD

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Reviews

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Companies worldwide trust WZ-IT

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The Problem

Technical debt is slowing you down

Your application has been running for 10 years and generates revenue.

"Never touch a running system" as a survival strategy
Outdated libraries no longer receive security updates.
Nobody finds their way any more
New developers get lost in the spaghetti code or quit.
The database is the bottleneck
Scaling is impossible, performance problems pile up.
A complete rewrite is risky and expensive
It cannot go on like this. But what to do?

Dev + Ops Under One Roof

Our Modernization Services

We can operate and modernise legacy systems: the old app stays stable while the new one is built.

Analyse

Code & Infrastructure Audit
We analyze your source code with static code analysis (SonarQube), identify the biggest risks, and create a prioritized modernization roadmap.
Monitoring & Observability
Introduction of modern logging, metrics, and tracing. Finally see what's happening in your application - instead of just guessing.

Stabilise

Containerization (Lift & Shift)
We package your legacy app in Docker containers. Your 10-year-old app runs safely on modern servers - with all its old dependencies.
Security Hardening
EOL PHP and Java versions without security updates? We migrate to current versions or isolate the app in protected containers.

Replace

Strangler Fig Pattern
Instead of a big-bang rewrite, we build new features as modern microservices alongside the old app. An API gateway decides which traffic goes where.
Database Modernization
Migration from old MySQL/Oracle to modern PostgreSQL solutions. Including schema migration, data cleaning, and query optimization.
Code Refactoring
Gradual introduction of typing (PHP Type Hints, TypeScript), tests, and clean code patterns. Spaghetti becomes readable and maintainable.

Hand over

CI/CD Pipeline Setup
From FTP uploads to automated deployments. We set up GitLab/GitHub pipelines that automate the transition and catch errors early.
Team Enablement
We work as an expert team for the difficult architectural changes. Your team learns alongside and gradually takes over - no vendor lock-in.

Tech Stack Migration

Before → After

The specific migration depends on your existing stack. We analyze and recommend individually.

Legacy (Your Current State)	Modern (Our Goal)
PHP 5.6 / 7.x (spaghetti code)	PHP 8.3 (Laravel/Symfony) or Node.js
Java EE / JBoss monolith	Spring Boot / Go microservices
"Pet" servers (manually maintained)	Docker / Kubernetes (cattle)
FTP uploads & manual deployments	CI/CD pipelines (GitLab/GitHub)
jQuery / old Bootstrap	React / Vue.js / Tailwind

Our Strategies

We don't suggest throwing everything away. We use proven patterns.

01
Lift & Shift
Containerization: The first step to stability. We package your legacy application (e.g., Legacy PHP, Java EE) into Docker containers. Independence from the host OS. We can shut down that ancient server and run your app safely on a modern Hetzner/AWS cluster. Docker · Podman · Custom Base-Images
02
Strangler Fig Pattern
Gradual Replacement: Instead of a "Big Bang" rewrite, we build new features as modern microservices alongside the old app. An API gateway (Traefik/Nginx) decides: Old traffic → Old App. New traffic → New Service. The new architecture gradually "strangles" the old software. API Gateway · Traefik · Microservices
03
Database Modernization
Data Migration: We migrate your data from outdated, unmanaged databases (old MySQL/Oracle) to modern, scalable solutions. Schema migration, data cleaning, and query optimization for Managed PostgreSQL (Supabase/Hetzner) or time-series DBs. PostgreSQL · Supabase · Schema migration

After go-live or takeover

Maintain software continuously and evolve it predictably

Managed Code Care combines dependency and CVE care, technical fixes and controlled releases. Ongoing development can be added as the second level.

Managed Code Carefrom €699.90 excl. VAT / monthCode Care or ongoing development

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Target platform

Kubernetes as the target platform

Modernization does not end at the container

When Kubernetes fits the target architecture, we plan the application, data, delivery, networking, cutover and operations as one coherent refit - on Proxmox, bare metal, European cloud or existing EKS, AKS and GKE environments.

Explore Kubernetes modernization →

Frequently Asked Questions

Answers to the most important questions about legacy modernization

TopicsStrategy & Risk Infrastructure & Containers Frontend & UI Process & Costs

Strategy & Risk

Infrastructure & Containers

Frontend & UI

Process & Costs

Knowledge

Target platforms and next steps

Target platforms

After the modernisation

Reviews & projects

Software projects with reliable outcomes

Proof for modernization, API extension, architecture, deployment and ongoing operations.

WZ-IT moved our studio infrastructure from decentralised individual devices to a central platform: every site is securely connected via VPN, new devices are onboarded automatically and an entire site is provisioned from a template, without manual steps on location. What impressed me most is the breadth and depth of their knowledge: Timo and Robin are not a typical IT provider who sets up a server and leaves. The two of them think their way into highly complex infrastructure and software topics, work through every requirement we put in front of them, and build networking, provisioning and operations so that everything fits together in the end. WZ-IT is an excellent partner for complex software, network and architecture projects.

Steve KirchnerManaging Director, nextGYM GmbH

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International

Built in Germany's Ruhr Valley. Running worldwide.

WZ-IT designs, develops and operates infrastructure and software for clients in Germany and internationally. We deliver projects remotely and continue supporting them in ongoing operations after go-live.