.NET Framework to .NET Core Migration Services
Migrate legacy .NET Framework apps to modern .NET Core (.NET 8) with a phased, zero-downtime approach. Faster, cheaper to host, and built for the next decade.
Get a Free Quote →.NET Framework to .NET Core Migration Services
.NET Framework 4.8 was the last version Microsoft will ever ship on that runtime. If your business-critical application still runs on it, every year you wait adds technical debt, security risk, and hosting cost. V2S Infosystem Private Limited migrates legacy .NET Framework applications to modern .NET 8/9 Core with a phased, tested, zero-downtime approach.
Get a Free Migration AssessmentWhat Is .NET Framework to .NET Core Migration?
.NET Framework is a Windows-only runtime that Microsoft has placed in maintenance mode — it receives only security patches, no new features, and no performance work. .NET Core (now unified simply as ".NET", currently at version 8 with .NET 9 available) is the actively developed, cross-platform successor that runs on Windows, Linux, and macOS, and inside Docker containers.
Migration means re-platforming your existing codebase — ASP.NET MVC/Web Forms, WCF services, console apps, or Windows services — onto the modern .NET runtime, updating incompatible NuGet packages, replacing framework-specific APIs, and re-architecting anything tightly coupled to IIS, the Windows Registry, or `System.Web`. It is not a rewrite from scratch — a well-planned migration reuses 60-80% of your business logic and data layer largely unchanged.
Independent benchmarks put .NET 8 at 2-5x faster than .NET Framework 4.8 for typical web workloads, which directly reduces the number of servers or the size of the App Service plan you need to run the same traffic.
Signs Your Application Needs This Migration
Locked to Windows Hosting
You're paying for Windows Server licenses and IIS when Linux containers would cost a fraction as much to run the same app.
Rising Server Costs
Traffic is growing and you keep scaling up VM size instead of scaling efficiently, because Framework's throughput per core is lower than modern .NET.
Security Patch Anxiety
.NET Framework 4.8 gets security-only fixes tied to the Windows OS lifecycle — no new hardening, no modern TLS/crypto defaults by design.
Can't Hire for the Stack
New graduates and senior engineers alike are trained on modern .NET, not Web Forms or WCF — your hiring pool shrinks every year you stay put.
Blocked From Modern Tools
Can't adopt containers, Kubernetes, minimal APIs, native AOT compilation, or the latest AI/ML libraries — most only target current .NET.
Maintenance Costs Climbing
Every workaround for missing Framework features adds custom code that someone has to maintain forever.
What We Migrate
Every migration engagement is scoped to your specific codebase — here's what we commonly handle.
ASP.NET MVC / Web Forms → ASP.NET Core
Rebuild the request pipeline on Kestrel, replace `System.Web` dependencies, migrate Razor views and Web Forms controls to Razor Pages or MVC/Blazor.
WCF Services → gRPC or REST APIs
WCF has no direct .NET Core equivalent — we re-platform service contracts to gRPC (best performance) or ASP.NET Core Web API (widest compatibility).
Entity Framework 6 → EF Core
Migrate data access layers, rewrite LINQ queries that behave differently under EF Core, and validate migrations against production-scale data.
Windows Services → Worker Services
Background jobs and scheduled tasks move to the cross-platform Generic Host / BackgroundService model, deployable as containers.
NuGet Package Compatibility Audit
We inventory every third-party dependency, flag Framework-only packages, and find modern replacements or write compatibility shims where needed.
Containerization & CI/CD
Package the migrated app into Docker images and set up a CI/CD pipeline for repeatable, automated deployments to Azure, AWS, or on-prem Kubernetes.
Our Migration Process
Codebase & Dependency Assessment
We run automated compatibility analysis across your solution, inventory every NuGet package and Framework-specific API call, and produce a scored migration-complexity report before any commercial commitment.
Migration Roadmap & ROI Estimate
You get a phased plan — which modules move first, what stays on Framework temporarily behind a compatibility shim, and a projected hosting-cost saving so the business case is clear upfront.
Incremental Migration in Parallel
We migrate module by module using the strangler-fig pattern — old and new run side by side behind a routing layer, so your production system never goes down mid-migration.
Regression & Performance Testing
Every migrated module is tested against the original for behavioral parity, then load-tested to confirm the expected throughput gains before it takes production traffic.
Cutover & Post-Migration Support
Final cutover happens on a low-traffic window with a rollback plan ready. We stay on for a defined hypercare period to catch anything the test suite missed.
When Migration Pays For Itself
| Cost Factor | On .NET Framework | After Migration to .NET 8 |
|---|---|---|
| Hosting OS | Windows Server (licensed) | Linux containers or Windows — your choice |
| Throughput per core | Baseline | 2-5x higher on typical web workloads |
| Deployment target | IIS on Windows only | Docker, Kubernetes, Azure App Service, AWS, on-prem |
| Break-even threshold | Industry guidance puts migration ROI positive once current annual licensing + hosting + maintenance spend exceeds roughly $50,000/year — most mid-size line-of-business apps hit this within 18-24 months post-migration. | |
Tech Stack
.NET 8/9, ASP.NET Core, EF Core, C#, gRPC, Docker, Kubernetes, Azure DevOps/GitHub Actions for CI/CD, and — where the migrated application has an AI/automation roadmap — Semantic Kernel, OpenAI, LangChain, and N8N for adding intelligent workflows on top of the modernized codebase.
Common Migration Myths, Corrected
"Migration means a full rewrite."
Not true for most applications. A well-scoped migration reuses 60-80% of business logic and the data layer largely unchanged — the work is mostly in the framework-specific plumbing (routing, hosting, WCF, Web Forms controls), not the domain logic that actually runs your business.
"We can't migrate because we use WCF/Web Forms."
These are the two hardest pieces to migrate, but neither is a dead end. WCF re-platforms to gRPC or Web API; Web Forms pages are rebuilt as Razor Pages or Blazor. Both require real engineering work, which is exactly why an upfront assessment matters before committing to a timeline.
"It's cheaper to just keep patching Framework."
Short-term, maybe. Long-term, you're paying compounding interest on technical debt: rising Windows Server/IIS licensing, an ever-shrinking hiring pool for Framework-era skills, and every year of deferred migration adds more code that eventually has to be touched anyway.
"Migration tools can do this automatically."
Automated tooling helps with mechanical changes — namespace updates, obvious package swaps — but Microsoft itself deprecated the standalone Upgrade Assistant. Anything involving WCF, Web Forms, or deep IIS coupling needs an engineer making architectural decisions, not a script.
The Risk of Waiting Another Year
.NET Framework 4.8 is the final version on that runtime — Microsoft has confirmed there will be no 4.9. It still receives security patches tied to the underlying Windows OS lifecycle, but that is fundamentally different from active development: no new performance work, no new language features, and an increasingly narrow pool of engineers who still want to work in it.
Every additional year on Framework means more new code written against an aging platform, more NuGet packages that quietly drop Framework support in their next major version, and a wider performance gap versus competitors already running on .NET 8/9's improved throughput. None of this is urgent in the way a production outage is urgent — which is exactly why it tends to get deprioritized until a compliance audit, a security review, or a hosting renewal forces the question.
Starting with an assessment now — even months before you plan to actually migrate — gives you a real cost/timeline number to work with instead of a guess, and lets you time the migration around a natural low-risk window (a slow season, a planned infrastructure refresh) rather than a forced, rushed one.
Engagement Models
Fixed-scope migration project — best when the assessment phase produces a clear, bounded scope. You get a fixed price and timeline for the full migration.
Phased retainer — for large, multi-module systems migrated over several quarters alongside ongoing feature work, billed monthly against an agreed roadmap.
Team augmentation — embed our .NET Core migration engineers directly into your existing team if you'd rather keep the work in-house with expert support.
Why V2S Infosystem
V2S Infosystem Private Limited has built and maintained production .NET systems since 2012 (as V2S Technologies) and has run migrations for both greenfield product teams and legacy line-of-business applications.
SOLID/DRY, Modular Architecture
Every migrated module is re-architected with clean separation of concerns, not just recompiled as-is against a newer runtime.
Assessment Before Commitment
You get a scoped complexity report and cost estimate before signing anything — no open-ended "we'll figure it out as we go" engagements.
Zero-Downtime Cutover
Strangler-fig migration means your business keeps running on the old system until each new module is proven in production.
3+ Year Client Retention
Long-term client relationships built on delivering working software on schedule, not one-off projects that disappear after go-live.
Frequently Asked Questions
How long does a .NET Framework to .NET Core migration take?
Small applications (a handful of controllers, one database) typically take 4-8 weeks. Mid-size line-of-business systems with WCF services and complex EF6 data layers run 3-6 months. Large, multi-module enterprise systems are migrated in phases over 6-18 months so nothing has to stop working while the migration is in progress.
Will we lose any functionality during migration?
No — the goal of every migration we run is behavioral parity first, performance gains second. We write regression tests against the existing application's actual behavior before touching code, so any deviation gets caught before it reaches production.
What happens to WCF services — there's no direct .NET Core equivalent?
Correct, WCF is Windows-only and unsupported on modern .NET. We re-platform WCF service contracts to either gRPC (best performance for internal service-to-service calls) or an ASP.NET Core Web API (best for broad client compatibility), matched to your actual consumers.
Do we have to migrate everything at once?
No, and we generally recommend against it. We use the strangler-fig pattern — new .NET Core modules run alongside the remaining Framework modules behind a routing layer, so you migrate incrementally and de-risk the whole project.
Is Microsoft's .NET Upgrade Assistant enough to do this ourselves?
Microsoft has actually deprecated the standalone Upgrade Assistant and now points teams toward the GitHub Copilot app modernization agent, which requires a paid subscription and still struggles with large, undocumented legacy codebases and anything touching WCF or Web Forms controls. Automated tooling is useful for the mechanical parts — package upgrades, namespace changes — but doesn't replace architectural judgment on what to re-platform versus rewrite.
How much does .NET Core migration cost?
It depends entirely on codebase size, WCF/Web Forms usage, and third-party package compatibility — which is exactly why we start every engagement with a paid or complimentary assessment rather than quoting blind. As a rough industry benchmark, migration typically becomes cost-positive once your current Framework app's combined licensing, hosting, and maintenance spend exceeds about $50,000/year.
Can we run on Linux after migrating, to cut hosting costs?
Yes — this is one of the biggest cost wins of migrating. Once you're off `System.Web` and Windows-specific dependencies, the application runs identically in a Linux container, removing Windows Server licensing entirely and opening up cheaper cloud compute options.
Ready to Modernize Your .NET Application?
Get a free codebase assessment from V2S Infosystem Private Limited and see exactly what a migration to .NET 8 would look like — and save — for your specific application.