Legacy Software Modernization
We rescue your legacy software. Modernization, refactoring, and cloud migration for outdated applications - without disrupting ongoing operations.
Leading companies worldwide trust WZ-IT
Technical debt is slowing you down
Your application has been running for 10 years and generates revenue. But: "Never touch a running system" is no longer a motto - it's become a survival strategy. Outdated libraries no longer receive security updates. New developers can't navigate the spaghetti code or they quit.
The database is the bottleneck, scaling is impossible. Performance issues are piling up. You know: This can't go on. But a complete rebuild is risky and expensive. What to do?
Dev + Ops Under One Roof
Most agencies can only build new. We can operate legacy systems AND modernize them. Thanks to Linux kernel expertise, CI/CD pipelines, and parallel operations, we ensure the old app stays stable while the new one emerges.
Our Modernization Services
Code & Infrastructure Audit
We analyze your source code with static code analysis (SonarQube), identify the biggest risks, and create a prioritized modernization roadmap.
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.
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.
CI/CD Pipeline Setup
From FTP uploads to automated deployments. We set up GitLab/GitHub pipelines that automate the transition and catch errors early.
Security Hardening
EOL PHP and Java versions without security updates? We migrate to current versions or isolate the app in protected containers.
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.
Monitoring & Observability
Introduction of modern logging, metrics, and tracing. Finally see what's happening in your application - instead of just guessing.
Before → After
Legacy (Your Current State)
Modern (Our Goal)
The specific migration depends on your existing stack. We analyze and recommend individually.
We don't suggest throwing everything away. We use proven patterns.
Strangler Fig Pattern
Gradual ReplacementInstead 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.
Database Modernization
Data MigrationWe 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.
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.
How can we help you?
Frequently Asked Questions
Answers to the most important questions about legacy modernization
Topics
Strategy & Risk
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.
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.
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.
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).
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.
Infrastructure & Containers
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.
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.
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).
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.
Frontend & UI
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).
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.
Process & Costs
With a Code & Infrastructure Audit. We examine the source code and servers, identify the biggest risks ("low-hanging fruit"), and create a modernization roadmap.
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").
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.
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.
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.
Let's talk about your project - honest and no strings attached
- Straight with Timo and Robin - no sales team, no pitch
- An honest take, including when we are not the right fit
- Concrete next steps for infrastructure, software or AI
No risk: worst case, you leave with a clearer understanding of your project than before.
“WZ-IT's advice on our Azure migration was technically sound and completely non-binding right from the intro call - we took away a great deal.”
Industry-leading companies worldwide rely on us
“Professional, honest and technically thoroughly sound: WZ-IT set up our Proxmox and backup infrastructure securely and future-proof. The consulting from Timo and Robin was objective and needs-driven, the implementation smooth and the final documentation exemplary. You can tell immediately that business-critical infrastructure is thought through holistically from the outset here and implemented with clear ownership.”
Pascal Block
Project Manager, Stadtwerke Brühl GmbH
Stadtwerke Brühl - municipal energy and infrastructure utility.
“Communication with WZ-IT was open, friendly and professional from the very beginning. Mr. Wevelsiep and Mr. Zins responded to every one of our questions patiently, promptly and respectfully, and contributed their own suggestions and good ideas on how to modernize our server infrastructure and adapt it even better to our needs. Throughout, WZ-IT consistently kept our need for data sovereignty and GDPR compliance in mind. Even short-notice adjustments and change requests from our side were implemented quickly and patiently and integrated consistently into the overall concept. From planning to the final handover, every step was documented transparently and comprehensively - so if a provider change should ever become necessary, the documentation would let us onboard a successor into our infrastructure very quickly. We are extremely satisfied with WZ-IT and hope to continue working together for a long time.”
Christoph Mußmann
Project Officer, DGHO e.V.
DGHO - German Society for Hematology and Medical Oncology.
“I got to know Timo and Robin as dedicated and professional partners who make a lot of things possible for their clients that initially seem impossible. I felt very well advised. The services offered have thoroughly convinced me. (translated)”
Andrea Pawlowski
Communications Manager, Golem.de
Golem.de - leading German IT news outlet.
“While looking for a partner to integrate a local AI solution, we came across Timo and Robin - and could not have made a better decision. They quickly understood our requirements and solved technical challenges competently and pragmatically. We were particularly impressed by the straightforward collaboration, their high level of expertise and the speed of implementation. We are delighted to have Timo and Robin at our side as reliable business partners and look forward to our next projects together. (translated)”
Henrik Jeche
Head of IT Administration
ml&s - full-service provider for the electronics industry.
“With Timo and Robin, you're not only on the safe side technically - you also get the best human support! Whether it's quick help in everyday life or complex IT solutions: the guys from WZ-IT think along with you, act quickly and speak a language you understand. The collaboration is uncomplicated, reliable and always on an equal footing. That makes IT fun - and above all: it works! Big thank you to the team! (translated)”
Sonja Aßer
Data Manager, ARGE
ARGE Neue Medien - master data & digital standards for plumbing and building technology.
“I recently worked with Timo and the WZ-IT team, and honestly, it turned out to be one of the best tech decisions I have made for my business. Right from the start, Timo took the time to walk me through every step in a simple and calm way. No matter how many questions I had, he never rushed me. The results speak for themselves. With WZ-IT, we reduced our monthly expenses from $1,300 down to $250. This was a huge win for us.”
Aleksandr Shuliko
CTO, EVA Real Estate, UAE
EVA Real Estate - leading real-estate agency in Dubai.
“WZ-IT manages our Proxmox cluster reliably and professionally. The team handles continuous monitoring and regular updates for us and responds very quickly to any issues or inquiries. They also configure new nodes, systems, and applications that we need to add to our cluster. With WZ-IT's proactive support, our cluster and the business-critical applications running on it remain stable, and high availability is consistently ensured. We value the professional collaboration and the noticeable relief it brings to our daily operations.”
Pascal Hakkers
Aphy AG, Switzerland
Aphy AG - AI platform for hotel back-office.
“WZ-IT provided very competent support in implementing our server and virtualization infrastructure. As part of the project, a Proxmox-based virtualization environment was set up along with a virtual machine for our application systems. Additionally, a structured backup concept was implemented. A particular focus was on security: the setup of a VPN tunnel and the clean implementation of encryption and access concepts were professionally executed. The structured consulting as well as the reliable and swift implementation deserve special mention. We are very satisfied with the services provided and are happy to recommend WZ-IT.”
John Hellmerichs
Managing Director, AInergy GmbH
AInergy - consultancy for energy and facility management.
“We have had very good experiences with Mr. Wevelsiep and WZ-IT. The consultation was professional, clearly understandable, and at fair prices. The team not only implemented our requirements but also thought along and proactively. Instead of just processing individual tasks, they provided us with well-founded explanations that strengthened our own understanding. WZ-IT took a lot of pressure off us with their structured approach - that was exactly what we needed and is the reason why we keep coming back. (translated)”
Matthias Zimmermann
Managing Director, Annota GmbH
Annota - healthtech startup with an AI documentation assistant.
“Timo and Robin from WZ-IT set up a RocketChat server for us - and I couldn't be more satisfied! From the initial consultation to the final implementation, everything was absolutely professional, efficient, and to my complete satisfaction. I particularly appreciate the clear communication, transparent pricing, and the comprehensive expertise that both bring to the table. Even after the setup, they take care of the maintenance, which frees up my time enormously and allows me to focus on other important areas of my business - with the good feeling that our IT is in the best hands. I can recommend WZ-IT without reservation and look forward to continuing our collaboration! (translated)”
Sebastian Maier
Managing Director, Yonju GmbH
Yonju - business coaching and AI products.
“Counting on WZ-IT team was crucial, their expertise and solutions gave us the pace to deploy in production our services, even suggesting and performing improvements over our configuration and setup. We expect to keep counting on them for continuous maintenance of our services and implementation of new solutions.”
Gabriel Sanz Señor
Managing Director, Odiseo Solutions
Odiseo Solutions - software engineering for the space industry.
“Professional, honest and technically thoroughly sound: WZ-IT set up our Proxmox and backup infrastructure securely and future-proof. The consulting from Timo and Robin was objective and needs-driven, the implementation smooth and the final documentation exemplary. You can tell immediately that business-critical infrastructure is thought through holistically from the outset here and implemented with clear ownership.”
Pascal Block
Project Manager, Stadtwerke Brühl GmbH
Stadtwerke Brühl - municipal energy and infrastructure utility.
“Communication with WZ-IT was open, friendly and professional from the very beginning. Mr. Wevelsiep and Mr. Zins responded to every one of our questions patiently, promptly and respectfully, and contributed their own suggestions and good ideas on how to modernize our server infrastructure and adapt it even better to our needs. Throughout, WZ-IT consistently kept our need for data sovereignty and GDPR compliance in mind. Even short-notice adjustments and change requests from our side were implemented quickly and patiently and integrated consistently into the overall concept. From planning to the final handover, every step was documented transparently and comprehensively - so if a provider change should ever become necessary, the documentation would let us onboard a successor into our infrastructure very quickly. We are extremely satisfied with WZ-IT and hope to continue working together for a long time.”
Christoph Mußmann
Project Officer, DGHO e.V.
DGHO - German Society for Hematology and Medical Oncology.
“I got to know Timo and Robin as dedicated and professional partners who make a lot of things possible for their clients that initially seem impossible. I felt very well advised. The services offered have thoroughly convinced me. (translated)”
Andrea Pawlowski
Communications Manager, Golem.de
Golem.de - leading German IT news outlet.
“While looking for a partner to integrate a local AI solution, we came across Timo and Robin - and could not have made a better decision. They quickly understood our requirements and solved technical challenges competently and pragmatically. We were particularly impressed by the straightforward collaboration, their high level of expertise and the speed of implementation. We are delighted to have Timo and Robin at our side as reliable business partners and look forward to our next projects together. (translated)”
Henrik Jeche
Head of IT Administration
ml&s - full-service provider for the electronics industry.
“With Timo and Robin, you're not only on the safe side technically - you also get the best human support! Whether it's quick help in everyday life or complex IT solutions: the guys from WZ-IT think along with you, act quickly and speak a language you understand. The collaboration is uncomplicated, reliable and always on an equal footing. That makes IT fun - and above all: it works! Big thank you to the team! (translated)”
Sonja Aßer
Data Manager, ARGE
ARGE Neue Medien - master data & digital standards for plumbing and building technology.
“I recently worked with Timo and the WZ-IT team, and honestly, it turned out to be one of the best tech decisions I have made for my business. Right from the start, Timo took the time to walk me through every step in a simple and calm way. No matter how many questions I had, he never rushed me. The results speak for themselves. With WZ-IT, we reduced our monthly expenses from $1,300 down to $250. This was a huge win for us.”
Aleksandr Shuliko
CTO, EVA Real Estate, UAE
EVA Real Estate - leading real-estate agency in Dubai.
“WZ-IT manages our Proxmox cluster reliably and professionally. The team handles continuous monitoring and regular updates for us and responds very quickly to any issues or inquiries. They also configure new nodes, systems, and applications that we need to add to our cluster. With WZ-IT's proactive support, our cluster and the business-critical applications running on it remain stable, and high availability is consistently ensured. We value the professional collaboration and the noticeable relief it brings to our daily operations.”
Pascal Hakkers
Aphy AG, Switzerland
Aphy AG - AI platform for hotel back-office.
“WZ-IT provided very competent support in implementing our server and virtualization infrastructure. As part of the project, a Proxmox-based virtualization environment was set up along with a virtual machine for our application systems. Additionally, a structured backup concept was implemented. A particular focus was on security: the setup of a VPN tunnel and the clean implementation of encryption and access concepts were professionally executed. The structured consulting as well as the reliable and swift implementation deserve special mention. We are very satisfied with the services provided and are happy to recommend WZ-IT.”
John Hellmerichs
Managing Director, AInergy GmbH
AInergy - consultancy for energy and facility management.
“We have had very good experiences with Mr. Wevelsiep and WZ-IT. The consultation was professional, clearly understandable, and at fair prices. The team not only implemented our requirements but also thought along and proactively. Instead of just processing individual tasks, they provided us with well-founded explanations that strengthened our own understanding. WZ-IT took a lot of pressure off us with their structured approach - that was exactly what we needed and is the reason why we keep coming back. (translated)”
Matthias Zimmermann
Managing Director, Annota GmbH
Annota - healthtech startup with an AI documentation assistant.
“Timo and Robin from WZ-IT set up a RocketChat server for us - and I couldn't be more satisfied! From the initial consultation to the final implementation, everything was absolutely professional, efficient, and to my complete satisfaction. I particularly appreciate the clear communication, transparent pricing, and the comprehensive expertise that both bring to the table. Even after the setup, they take care of the maintenance, which frees up my time enormously and allows me to focus on other important areas of my business - with the good feeling that our IT is in the best hands. I can recommend WZ-IT without reservation and look forward to continuing our collaboration! (translated)”
Sebastian Maier
Managing Director, Yonju GmbH
Yonju - business coaching and AI products.
“Counting on WZ-IT team was crucial, their expertise and solutions gave us the pace to deploy in production our services, even suggesting and performing improvements over our configuration and setup. We expect to keep counting on them for continuous maintenance of our services and implementation of new solutions.”
Gabriel Sanz Señor
Managing Director, Odiseo Solutions
Odiseo Solutions - software engineering for the space industry.
“Professional, honest and technically thoroughly sound: WZ-IT set up our Proxmox and backup infrastructure securely and future-proof. The consulting from Timo and Robin was objective and needs-driven, the implementation smooth and the final documentation exemplary. You can tell immediately that business-critical infrastructure is thought through holistically from the outset here and implemented with clear ownership.”
Pascal Block
Project Manager, Stadtwerke Brühl GmbH
Stadtwerke Brühl - municipal energy and infrastructure utility.
“Communication with WZ-IT was open, friendly and professional from the very beginning. Mr. Wevelsiep and Mr. Zins responded to every one of our questions patiently, promptly and respectfully, and contributed their own suggestions and good ideas on how to modernize our server infrastructure and adapt it even better to our needs. Throughout, WZ-IT consistently kept our need for data sovereignty and GDPR compliance in mind. Even short-notice adjustments and change requests from our side were implemented quickly and patiently and integrated consistently into the overall concept. From planning to the final handover, every step was documented transparently and comprehensively - so if a provider change should ever become necessary, the documentation would let us onboard a successor into our infrastructure very quickly. We are extremely satisfied with WZ-IT and hope to continue working together for a long time.”
Christoph Mußmann
Project Officer, DGHO e.V.
DGHO - German Society for Hematology and Medical Oncology.
“I got to know Timo and Robin as dedicated and professional partners who make a lot of things possible for their clients that initially seem impossible. I felt very well advised. The services offered have thoroughly convinced me. (translated)”
Andrea Pawlowski
Communications Manager, Golem.de
Golem.de - leading German IT news outlet.
“While looking for a partner to integrate a local AI solution, we came across Timo and Robin - and could not have made a better decision. They quickly understood our requirements and solved technical challenges competently and pragmatically. We were particularly impressed by the straightforward collaboration, their high level of expertise and the speed of implementation. We are delighted to have Timo and Robin at our side as reliable business partners and look forward to our next projects together. (translated)”
Henrik Jeche
Head of IT Administration
ml&s - full-service provider for the electronics industry.
“With Timo and Robin, you're not only on the safe side technically - you also get the best human support! Whether it's quick help in everyday life or complex IT solutions: the guys from WZ-IT think along with you, act quickly and speak a language you understand. The collaboration is uncomplicated, reliable and always on an equal footing. That makes IT fun - and above all: it works! Big thank you to the team! (translated)”
Sonja Aßer
Data Manager, ARGE
ARGE Neue Medien - master data & digital standards for plumbing and building technology.
“I recently worked with Timo and the WZ-IT team, and honestly, it turned out to be one of the best tech decisions I have made for my business. Right from the start, Timo took the time to walk me through every step in a simple and calm way. No matter how many questions I had, he never rushed me. The results speak for themselves. With WZ-IT, we reduced our monthly expenses from $1,300 down to $250. This was a huge win for us.”
Aleksandr Shuliko
CTO, EVA Real Estate, UAE
EVA Real Estate - leading real-estate agency in Dubai.
“WZ-IT manages our Proxmox cluster reliably and professionally. The team handles continuous monitoring and regular updates for us and responds very quickly to any issues or inquiries. They also configure new nodes, systems, and applications that we need to add to our cluster. With WZ-IT's proactive support, our cluster and the business-critical applications running on it remain stable, and high availability is consistently ensured. We value the professional collaboration and the noticeable relief it brings to our daily operations.”
Pascal Hakkers
Aphy AG, Switzerland
Aphy AG - AI platform for hotel back-office.
“WZ-IT provided very competent support in implementing our server and virtualization infrastructure. As part of the project, a Proxmox-based virtualization environment was set up along with a virtual machine for our application systems. Additionally, a structured backup concept was implemented. A particular focus was on security: the setup of a VPN tunnel and the clean implementation of encryption and access concepts were professionally executed. The structured consulting as well as the reliable and swift implementation deserve special mention. We are very satisfied with the services provided and are happy to recommend WZ-IT.”
John Hellmerichs
Managing Director, AInergy GmbH
AInergy - consultancy for energy and facility management.
“We have had very good experiences with Mr. Wevelsiep and WZ-IT. The consultation was professional, clearly understandable, and at fair prices. The team not only implemented our requirements but also thought along and proactively. Instead of just processing individual tasks, they provided us with well-founded explanations that strengthened our own understanding. WZ-IT took a lot of pressure off us with their structured approach - that was exactly what we needed and is the reason why we keep coming back. (translated)”
Matthias Zimmermann
Managing Director, Annota GmbH
Annota - healthtech startup with an AI documentation assistant.
“Timo and Robin from WZ-IT set up a RocketChat server for us - and I couldn't be more satisfied! From the initial consultation to the final implementation, everything was absolutely professional, efficient, and to my complete satisfaction. I particularly appreciate the clear communication, transparent pricing, and the comprehensive expertise that both bring to the table. Even after the setup, they take care of the maintenance, which frees up my time enormously and allows me to focus on other important areas of my business - with the good feeling that our IT is in the best hands. I can recommend WZ-IT without reservation and look forward to continuing our collaboration! (translated)”
Sebastian Maier
Managing Director, Yonju GmbH
Yonju - business coaching and AI products.
“Counting on WZ-IT team was crucial, their expertise and solutions gave us the pace to deploy in production our services, even suggesting and performing improvements over our configuration and setup. We expect to keep counting on them for continuous maintenance of our services and implementation of new solutions.”
Gabriel Sanz Señor
Managing Director, Odiseo Solutions
Odiseo Solutions - software engineering for the space industry.
Let's Talk About Your Idea
Whether a specific IT challenge or just an idea - we look forward to the exchange. In a brief conversation, we'll evaluate together if and how your project fits with WZ-IT.
Leading companies trust WZ-IT
Timo Wevelsiep & Robin Zins
Managing Directors of WZ-IT