Modernising legacy .NET systems often involves a phased, low-downtime approach. Upgrading the codebase, services, and data in stages lets businesses keep operations online while transforming an old app into a fast, cloud-ready solution. In practice, .NET migration means moving an application from one .NET runtime or version to another (for example, from the old Windows-only .NET Framework to the newer cross-platform .NET platform).

Enterprises in 2026 should target .NET 8 (LTS) for stability or .NET 9 (STS) for early feature adoption. It is important to understand Microsoft's release cycle (LTS releases occur every even year). .NET 10 (the next planned LTS) will be the next planned upgrade path.

This process is more than a simple update: it's an opportunity to integrate modern capabilities (such as containerization, micro services, and cloud services) into existing software. By migrating, organisations gain better scalability, reliability, security, and lower costs as workloads run on up-to-date infrastructure.

In this article, we cover every aspect of .NET migration and development, from why it matters to how it's done, and explain how Digisoft Solution helps enterprises make the transition smoothly.

What is .NET Application Migration?

".NET migration" refers to moving an application from an older .NET environment to a newer one. Typically, this means porting software from the legacy .NET Framework (which only runs on Windows) to the latest .NET platform (formerly called .NET Core, now unified under .NET 10). The goal is to improve compatibility and performance.

For example, migrating to .NET 10 immediately unlocks cross-platform support (Windows, Linux, macOS), containerization, and cloud deployment options. It also brings performance gains: modern .NET has a leaner runtime (with the high-performance Kestrel web server) that often outpaces the old Framework, especially for high-throughput APIs.

When defining migration, experts emphasise that nothing inherently breaks; existing functionality remains, but runs on a modern stack. In the migration process, everything that users love about your product doesn't disappear during migration. Instead, you retain key features while gaining flexibility: you can add new features faster, scale on-demand, and integrate with modern tools and cloud services.

Contrary to the previous .NET Framework (Windows-only), the new .NET runtime is compatible with Windows, Linux, and macOS. In the simplest terms, .NET is Microsoft's open-source development platform that is cross-platform and enables enterprises to develop and run applications quickly across operating systems, devices, and cloud environments.

.NET's Major Technical Strengths

Cross-Platform Support

.NET apps can run on Windows, Linux, and macOS without any code modifications. Developers can build applications on Windows using Visual Studio, or on macOS/Linux using Visual Studio Code and the .NET CLI, with the help of cross-platform tools.

High Performance

.NET's optimised runtime can handle massive workloads. Tests show that ASP.NET Core (the web framework used in modern .NET) is among the most efficient available. In real-world use, many enterprises experience significant speed increases after the migration.

For instance, upgrading to .NET 10 has yielded faster performance in certain projects, as shown by benchmarks such as BenchmarkDotNet, Azure Application Insights, and load-testing tools (k6, JMeter). It strengthens the application's position as an architecture-driven solution.

Cloud-Native and Microservices

.NET is specifically designed to work with microservices and cloud architectures. Microsoft states that .NET supports microservices and containerization across various platforms (Azure Service Fabric, Docker, Kubernetes, etc.).

It is a great choice for container environments. .NET is also compatible with modern design patterns, such as serverless services (e.g., Azure Functions) and microservices, which enable large-scale, distributed designs.

Scalability and Side-by-Side Versions

Modern .NET allows different versions of the runtime to run on the same computer. This allows side-by-side deployment of applications without conflicts, unlike the .NET Framework, which allows only one version per OS. Side-by-side .NET minimises the risk of upgrading and facilitates maintenance.

Security & Updates

.NET receives regular security updates. Newer frameworks enforce best practices (HTTPS by default and the most modern authentication methods) and allow developers to use the latest security libraries. A properly planned .NET transfer "hardens security": HTTPS is required by default, and known vulnerabilities are fixed.

.NET offers a rich ecosystem and community support, along with a wide collection of libraries (NuGet packages) and applications (Visual Studio, Azure DevOps). It works with the full Microsoft stack (Azure, SQL Server, SharePoint, and more) and open-source technologies. Microsoft's extensive documentation and contributions to the community guarantee a secure, long-term platform.

.NET (from .NET 5 onwards) blends the best features of the older Framework and .NET Core into a unified platform for desktop, web, mobile, and cloud. It can support a variety of workloads (web applications, APIs, mobile applications via Xamarin/.NET MAUI, IoT, ML, and more). With the unification of .NET, developers can build an integrated stack to create everything from websites to enterprise systems and desktop and mobile applications, using a common tooling and language.

Why Modernise or Migrate to .NET

Many organisations seek .NET migration services when existing software is at its limits. Common drivers include:

End-of-Life Frameworks

Many older .NET apps were built with earlier versions of the .NET Framework (e.g., 3.x, 4.0-4.7). After being removed from support, the frameworks are at risk of security and compliance issues. Moving to the latest .NET release can restore security and patching.

Scalability and Performance

Upgrading to the latest version of .NET provides tangible efficiency and performance gains. In fact, simply switching from the .NET Framework to .NET Core or .NET 10 can improve throughput by 25-30%. Modern .NET's more efficient runtime also utilises memory more efficiently. The performance gains often translate into fewer servers required (reducing the cost of hosting) and a better user experience.

Cloud and Cross-Platform Requirements

When your company is moving toward cloud-based or multi-platform deployments, the latest version of .NET is ideal. The latest version of .NET has been built for cloud readiness, enabling large-scale, distributed services. With .NET applications, apps can be run on Azure (App Services, AKS, Functions) or AWS (Elastic Beanstalk, Lambda) with minimal modifications. This gives you features such as automatic scaling and worldwide availability.

Architecture Modernization

Monolithic designs hinder adaptability. A .NET migration project typically involves restructuring, splitting monoliths into modular components or microservices to simplify maintenance and scaling. Modern patterns such as Kubernetes containers, Docker containers, and serverless solutions become feasible after the migration.

Security and Compliance

The latest .NET platforms are built on the latest security frameworks. Moving to a new platform, teams can ensure:

• HTTPS worldwide
• Up-to-date security measures (OAuth, OpenID)
• SAST via SonarQube
• CI/CD via GitHub Actions
• Manage Secrets with Azure Key Vault
• Protected container runtimes
• Latest encryption standards

For regulated industries (finance, healthcare, etc.), these upgrades help meet auditing requirements. Most customers benefit from stronger security, which directly supports business goals such as audit readiness.

Innovation and New Features

The final point is that migration offers an opportunity to increase value. Teams frequently use the upgrade process to add new features they want or to improve the user experience. .NET development companies stress that, after the upgrade, the application can be unmistakably better, not just the same application running with a different runtime. For instance, you could include real-time APIs, new UI elements, or even integrate AI capabilities into the transfer process. The result is an app that is more efficient, secure, and cloud-ready.

Moving to the latest .NET platform can dramatically improve application performance and scalability. After the migration, your application will run faster, scale better, and be built to support future business needs. This is accomplished by updating the codebase, improving the system architecture (e.g., decomposing monoliths and services), and enforcing best security practices.

Our .NET Development Services

An all-inclusive .NET development firm provides complete services for customised software applications. This includes analysis of design, development, testing, deployment, and continuous support. The most important services offered typically comprise:

Customised Web and API Development

Creating portals, web-based applications, and RESTful APIs by using ASP.NET Core, MVC, Blazor, Entity Framework, and other .NET technologies. They are extremely efficient and safe. The company uses industry-standard ASP.NET development methods to build solutions that meet a variety of domain needs and the highest security and user experience requirements.

Mobile App Development

Building cross-platform mobile apps using the Xamarin framework and .NET MAUI (the evolution of Xamarin). A .NET firm can create iOS, Android, and Windows apps using one C# codebase, leveraging native devices' capabilities. The top .NET teams also offer:

• Offline support
• Security features (OAuth2 MFA)
• API integration for the backend

Desktop and Enterprise Applications

Developing Windows desktop applications using WPF, WinForms, UWP, or Electron (via Blazor). Many older line-of-business (LOB) applications are updated or redesigned using .NET to support modern user interfaces. Expert .NET companies have extensive experience extending and supporting enterprise systems, including developing customised modules for platforms such as SharePoint, Dynamics CRM, Sitefinity CMS, and Umbraco CMS.

Cloud & Microservices Solutions

Designing cloud-native back-end systems for Azure and AWS. It may include:

• Azure App Services
• Kubernetes (AKS/EKS)
• Azure Functions (serverless)
• AWS Lambda (with .NET Core support)
• Azure SQL Database or Cosmos DB

The top .NET development teams use DevOps pipelines (Azure DevOps or GitHub Actions) to automate build, testing, and deployment.

UI Updates

Refreshing the user interfaces of applications already in use. Desktop applications developed with WinForms/WPF can be converted to run on .NET 8/10 or redesigned to use new Mobile or Blazor frontends. Web-based applications (old .NET WebForms and MVC) can be migrated to ASP.NET Core MVC and Razor Pages for improved performance and reliability.

Database and Integration

Task upgrading databases and access to data. It doesn't matter whether you're using SQL Server or moving to a cloud-based database (Azure SQL or Cosmos DB); the team is updating schemas, stored procedures, and Entity Framework (EF) settings to ensure data is fully compatible.

Integration Services

Ensuring that .NET applications are compatible with other enterprise systems. It involves connecting to:

• ERP/CRM systems
• External APIs
• Payment gateways
• Legacy services

The company incorporates ASP.NET solutions into business applications, such as ERP, CRM APIs, extensions, and CRM, to maximise data flow performance and efficiency.

Testing and Quality Assurance

Implementing manual and automated test procedures to test .NET applications. It includes:

• Unit tests (xUnit)
• Integration tests
• UI tests (Selenium or Playwright)
• Load and performance testing
• Security tests (SAST/DAST)

Each module is thoroughly checked to make sure it matches the expected behaviour.

Maintenance & Support

Providing ongoing support after deployment. It includes monitoring of performance bugs, updates, bug fixes, and improvements. The company provides comprehensive support throughout the pre and post development phases, including project maintenance, analysis, bug resolution, and quality assurance after deployment. It ensures that the software stays current and robust.

.NET development companies tailor the technology stack to suit the project's requirements. They use C# and ASP.NET Core, Entity Framework Core for data access, and create user interfaces with Blazor and JavaScript frameworks as needed. They also use modern tools such as Docker, Kubernetes, and CI/CD to ensure the solution is maintainable and scalable.

.NET Migration and Modernisation Services

.NET migration services can be used in a variety of scenarios to migrate existing applications to more modern .NET technologies or platforms. It covers the following services:

Upgrades to Old .NET Framework Apps

Straightforward lift-and-shift migrations of applications from earlier .NET Framework 4.x versions to the modern unified .NET platform (e.g., .NET 8 LTS or .NET 10 LTS). This typically involves the updating of:

• Project documents
• NuGet packages
• Configuration files

The goal is to maintain functionality while updating the libraries and runtime, with minimal code changes.

Modernisation and Refactoring Migrations

In-depth analysis that improves the framework and enhances the structure. It involves:

• Decomposing monolithic applications into microservices
• Redesigning the architecture
• Applying performance optimisations
• Strengthening security (e.g., by enforcing HTTPS and modern authentication)
• Patching vulnerabilities

Teams start by updating the codebase to the latest .NET to reap immediate memory and performance benefits. Then, they redesign the structure by splitting monoliths into modular services or refreshing tiered designs, so the solution scales cleanly and is easier to maintain.

Older Technology Porting

Transitioning software from non- .NET platforms to .NET. Most cases involve porting:

• VB6 or classic ASP applications
• Java, PHP, or ColdFusion applications to modern .NET
• VB.NET to C#
• ColdFusion to ASP.NET

This requires writing or translating business logic in C# and replacing the UI layers with ASP.NET or other modern frameworks. It brings old systems into the .NET ecosystem and unifies the technology stack.

Moving Databases and Data

During the migration process, teams update:

• Database schemas
• Stored procedures
• Data access code

The database to be migrated is either an on-premises SQL Server or a cloud database (Azure SQL or Amazon RDS), and the migration process will ensure that your data layer remains fully compatible. Tools that automate EF Core migrations are used to implement database changes.

Cloud Migration

Moving .NET applications to cloud-based environments. It involves switching from on-premises servers to Azure or AWS (IaaS, PaaS, or serverless). For instance, background processes that ran as Windows console jobs or services could be rewritten to use .NET Worker Services or Azure Functions, thereby embracing a serverless architecture. Web applications can be deployed via Azure App Service or AWS Elastic Beanstalk, typically in containers.

Containerization

Packing .NET apps into containers with Docker to facilitate deployment and consistent environments. .NET Core and later support containers right out of the box. Teams usually offer:

• Docker/Kubernetes deployment
• Microservices enablement
• DevSecOps and GitOps
• Observability
• Zero Trust practices

Integration of New Features

Migration projects typically also include the requested new features. In the process of modernising projects, teams can integrate:

• Modern APIs
• Improved UX/UI
• Cloud-based services (e.g., push notifications, identity services)

At Digisoft Solution, new features or user interface upgrades are integrated, ensuring the final product is as good as, or better than, the original.

Results of the Migration

The entire migration process is monitored, and key performance indicators are tracked. Clients typically evaluate metrics such as:

• Response times
• Throughput
• Transaction cycle times

When a migration is well executed, a business can see tangible results, such as fewer manual work hours, lower page load times, shorter cycle times, or higher orders per second.

Key Advantages of Expert .NET Professionals

There are various benefits of working with .NET professionals. The key advantages include:

End-to-End Knowledge

Top .NET companies manage entire projects internally. They provide full-stack code, testing, deployment, and maintenance as one-stop shops that manage the development of entire projects with end-to-end services. They provide the planning process, development of a full-stack testing, deployment, and maintenance.

Expertise and Experience

.NET firms have years of industry experience and a multitude of completed projects. Many companies hold Microsoft accreditations (Gold or Silver Partners) and publish case studies. They are aware of industry best practices and comply with requirements across industries (finance focuses on security, healthcare on privacy, etc.).

Modular Engagement Strategies

You can hire a .NET team in a variety of ways, such as:

• Joining a committed team of developers
• Contracting on a project basis
• Staff augmentation

An offshore .NET team can provide enterprise-grade expertise for less, with agile and efficient communication (daily stand-ups, overlapping hours) to stay informed. Teams aligned to time zones or hybrid offshore-onshore models can also be arranged. This flexibility allows you to increase or decrease resources as needed and maximise your budget.

Secure Processes & Tools

Professional teams employ disciplined development methods. They use Agile and Scrum methodologies as well as DevOps practices. They run static code analysers (such as the .NET Portability Analyser) on each commit and use an automated CI/CD pipeline (Azure DevOps and GitHub Actions) to develop tests, deploy, and build code. Practices include:

• Unit testing
• Code reviews
• Speed testing
• Ongoing monitoring throughout their workflow

Support & Maintenance

The best .NET development service partner doesn't disappear after launch. They offer:

• Support contracts
• Continuous maintenance
• Performance tuning
• Monitoring app health
• Infrastructure coordination
• Improvement suggestions

This means that your investment in .NET technology will continue to deliver benefits over time.

.NET Migration Process

A methodical process is essential. The typical phases in the .NET migration process are:

1. Assessment and Audit

Carefully review the current application's codebase, architecture, dependencies, and technical debt. Find out which libraries are in need of replacement, as well as the third-party services used, and also where the hotspots of performance are. This audit shows what should be transferred and what needs to be changed or eliminated.

2. Planning and Architecture

Based upon the audit, determine the new architecture that you wish to build. This involves:

• Migrating to .NET 10 (Current LTS) or .NET 9 (STS - Short-term support)
• Implementing microservices
• Migrating databases to Azure SQL
• Determining which components require an overhaul
• Including a transition strategy (e.g., big bang vs. iterative) and rollback plans

3. Migration of Components and Code

This is when developers upgrade the APIs, UI, and business logic of their application to the latest .NET runtime. For instance:

• Older ASP.NET Web Forms pages might be gradually rewritten in the ASP.NET Core MVC framework or even in Blazor
• Modern front-ends (React and Angular) may be introduced using the same backend logic
• Backend APIs (e.g., older WCF or ASMX APIs) are rebuilt into high-performance gRPC or REST services on .NET

The main goal is to keep the basic function intact. Users will be able to use the app with ease, but with a slight improvement.

4. Testing and Validation

After modifying the code, the newly migrated app is thoroughly tested:

• Functional tests assure that the features are functioning properly
• Tests for load and performance ensure that the system meets or exceeds standards
• Integration tests ensure that the new database APIs are connected correctly

This test checks that everything works as well or better than in the old version.

5. Support and Deployment

Once it is stable, the updated app is released to production (often on containers or cloud infrastructure). Following the launch, teams:

• Review the app's performance
• Collect user feedback
• Promptly address any problems
• Begin continuous maintenance with monitoring performance, patching, and planning the next steps

Throughout this process, automation tools can help speed up the task. For example, Microsoft's .NET Upgrade Assistant (and new Copilot-based tools) will automatically update projects' files and replace outdated APIs. Additionally, companies use analysis tools (the .NET Portability Analyser, Roslyn analysers, etc.) and CI/CD pipelines (Azure DevOps, GitHub Actions) to detect issues earlier and enforce quality standards.

Related Read: ASP.NET vs. PHP    

Why Digisoft Solution as Your .NET Development Partner

Given the complexity of .NET development and migration, selecting a seasoned partner is vital. Digisoft Solution, with over 12+ years of .NET experience, is positioned as an all-in-one .NET development firm. This is the way Digisoft Solution is different:

Deep .NET Expertise

Our senior .NET developers average 8+ years of experience delivering enterprise-grade modernisation projects. They stay up to date with the latest .NET technologies, such as:

• Blazor Microservices
• AI integration using ML.NET
• Azure OpenAI Service
• Vector databases like Pinecone
• Embedded semantic search
• AI-based document processing
• LLM-assisted business workflows

End-to-End Services

We offer full-lifecycle migration services, beginning with initial audits of the code and design, through migration planning and testing, and including continuous support. If it's a single project or a long-term collaboration, the team will cover every step.

A Performance-Driven Approach

In contrast to companies that simply update project files, we emphasise tuning. For example, we evaluate apps during migration to identify slow code paths and then optimise their performance. Our .NET developers also implement modern security measures (e.g., HTTPS everywhere) and, afterwards, refactor the application's structure (e.g., breaking monoliths) so it can scale quickly. It is an application that is faster, more secure, and cloud-ready.

Flexible Engagement Models

We can align with your team's needs, whether you require overseas development staff to ensure cost-effectiveness or experts in your local time zone for live collaboration. We provide:

• Fixed-price transfers
• Continuous managed services
• Expert-level expertise with transparent communication and planning

Proven Track Record

We have modernised applications across industries, from finance to healthcare. For larger companies, we start with one-off migrations to test the strategy and then expand to full-scale production, ensuring the smoothest delivery.

Unlike competitors who treat migration as a checklist exercise, our approach is transformative; we don't just move code. We often deliver an automated build process as part of the development. We also include the latest DevOps and security software, so the modern app isn't just present-day but also prepared for the future.

Partnering with Digisoft Solution means getting more than just a one-time upgrade, but means gaining a strategic partner. Their emphasis on simple architecture, tangible performance improvements, and extensive support aligns with customer requirements when modernising .NET applications.

Strategic .NET Migration for Long-Term Growth

The process of transferring and developing .NET applications can be a difficult but crucial step for businesses that rely upon Microsoft technology. Successful migrations provide not just a brand new runtime but a more flexible, efficient, secure, and cost-effective application. Through a well-planned process (project assessment, planning, porting and testing, and iteration) and using tools such as the .NET Upgrade Assistant, companies can reduce risk and minimise downtime.

Digisoft Solution's focus is on helping clients on this journey. With experienced .NET professionals and a results-driven approach, they ensure existing investments are protected and upgraded. The goal is to create an updated application that infuses new life into existing products, that is more efficient, safer, and suitable for the new cloud age. If you are a business looking to upgrade its .NET software, partnering with a trusted provider can make the difference and ensure a smooth, successful transition.

Frequently Asked Questions (FAQs)

1. What do you mean by .NET service for application migration?

.NET Application migration services involve transferring an existing application from an outdated framework, platform, or system to a modern .NET platform, such as .NET Core or .NET 9+. It includes code refactoring, database migrations, optimisation for performance, and updating integrations to meet the requirements of modern architectures like microservices, cloud hosting, and containerization.

2. Why should companies move to more modern .NET technology?

The move to more modern .NET technologies increases speed, security, scalability, and provides cross-platform support. The latest .NET versions provide improved memory management, increased developer productivity, and the ability to support cloud-based environments such as Azure and AWS. This results in lower TCO and a faster time-to-market.

3. How long will a typical .NET migration take?

The timeframe varies based on the complexity of the application, its size and dependencies. A typical migration can take 4 to 12 weeks for smaller apps, while larger enterprise systems can take 3 to 6 months. The initial assessment and planning are vital to accurately estimating timeframes.

4. What exactly is .NET modernisation of applications?

.NET Modernisation enables older applications to use the latest .NET Framework and .NET tools. This means rethinking monolithic applications into modular services, using cloud-native patterns, maximising performance, and integrating DevOps techniques to simplify deployments.

5. Can .NET applications be transferred into the cloud?

Yes, .NET applications are very capable of working with cloud services such as Microsoft Azure, AWS, and Google Cloud. The latest version of .NET supports cloud scaling containers (Docker), Kubernetes orchestration, and server less functions.

6. What are the advantages of the use of .NET Core or .NET 7+?

The benefits of using .NET Core or .NET 9+ include cross-platform support on Windows, Linux, and macOS. It enhances performance, reliability, speed, and security, and also provides long-term support. It works on unified frameworks for web, mobile, and desktop. Many powerful tools are available in Visual Studio / VS Code.

7. How do you ensure your data security when you are undergoing .NET migration?

We ensure data security with secure backups before migration and conduct validation tests at each stage to verify security. Our experts implement access control and encryption, an incremental migration strategy, and automatic regression testing.

8. Does the .NET service for migration include assistance and maintenance?

Yes. The best .NET service providers offer post-migration assistance, monitoring, the latest security patches, performance tuning, and feature enhancements, ensuring smooth, long-term operation.

9. What exactly is .NET modernisation of APIs?

API Modernisation converts obsolete API endpoints into scalable, secure, and documented services that use gRPC or REST, with modern authentication, versioning, and performance improvements, enabling more seamless integration with mobile, web, and IoT platforms.

10. How can .NET services increase the scalability of applications?

The latest .NET patterns, such as microservices, cloud-native deployments, containerization (Docker), and orchestration (Kubernetes), allow the application to expand horizontally and manage various workloads efficiently.