How to move from .NET Framework to .NET Core in 2024? Migration guide

April 18, 2024
How to move from .NET Framework to .NET Core in 2024? Migration guide

When businesses consider upgrading frameworks, they often weigh the transition from the well-established .NET Framework to the newer .NET Core, both offerings from Microsoft.

Since its introduction, .NET Core has gained traction among software developers who seek enhanced performance and a number of progressive features. With approximately 55% of developers favoring .NET Core over .NET Framework, its popularity continues to grow due to its ability to streamline software development for deployment across diverse platforms.

However, migrating an existing application from .NET Framework to .NET Core can pose challenges. While there are compelling reasons to make the switch, it's crucial to thoroughly understand the migration process before embarking on it.

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In this article, we'll delve into the intricacies of converting .NET Framework to .NET Core and offer insights to consider throughout the migration journey.

.NET Framework vs .Net Core: In what cases the migration makes sense

When considering the migration of your application infrastructure to the versatile .NET Core, various factors come into play. Sticking to .NET Framework might be preferable if your application heavily relies on libraries and packages unsupported by .NET Core, if your business requirements are adequately addressed, and if you have limited resources available for migration efforts.

While .NET Framework remains a mature and stable technology suitable for many applications, there are cases when transitioning to .NET Core offers distinct advantages.

.NET Framework
.NET Core
  • Relies on traditional performance metrics such as CPU and memory usage.
  • May experience slower startup times due to the heavier runtime and initialization process.
  • Based on modern performance optimization techniques, including efficient resource utilization and reduced overhead.
  • Generally experiences faster startup times due to its lightweight nature and optimized initialization process.
  • Traditional scaling methods, primarily vertical scaling, which involves adding more resources to a single server.
  • Limited scalability options due to its monolithic architecture, making it challenging to scale individual components independently.
  • Vertical scaling to handle increased loads.
  • Modern scaling techniques, including horizontal scaling, which involves distributing workloads across multiple servers.
  • Microservices architecture, allowing components to be scaled independently.
  • Horizontal scaling, enabling the addition of more servers to handle increased demand.
Updates and maintenance
Tied to the Windows OS updates
Independent updates that are faster and do not depend on the OS
Windows only
Windows, Linux, macOS
Released in 2002
Released in 2016
Open-source framework, created by Microsoft

Here are some situations where migrating to .NET Core proves advantageous:

  • When your app requires performance and scalability improvements: .NET Core's modular structure allows selective feature utilization for improved performance, leveraging strategies like componentization, virtualization, caching, load balancing, and database optimization.
  • When storage constraints exist: If your application targets devices with limited storage capacity, .NET Core's smaller footprint makes it ideal for IoT applications or devices with storage constraints.
  • When you want to use your app across multiple platforms: .NET Core supports seamless cross-platform development, enabling applications to run on Windows, macOS, or Linux without the need for separate codebases.
  • When your app should be supported by newer operating systems: .NET Core's libraries enable scalable application development targeting the latest operating system versions, ensuring compatibility with new features and enhancements.
  • When you aim for open-source collaboration: .NET Core's open-source nature fosters collaboration, allowing for rapid bug fixes and upgrades through community contributions.
  • When you are targeting microservices:  .NET Core offers a versatile framework that facilitates the development of microservices-based architectures. Its modular structure and lightweight design empower developers to create scalable and manageable services.
  • When you are using docker containers:.NET Core seamlessly integrates with Docker containers, providing a streamlined approach to packaging and deploying applications. 

Why to migrate from .NET Framework to .Net Core?

Developers may choose to migrate for several reasons, including:

Enhanced product innovation

Constant updates to .NET Core introduce new features and capabilities, facilitating product innovation more effectively and efficiently. 

Cost reduction

Retiring specific components of .NET Framework lowers costs by eliminating the need to support and maintain older components. This transition allows for embracing contemporary tools and technologies, leading to cost efficiencies and streamlining the development process.

Improved application performance

Non-blocking codes ensure high-speed applications run smoothly without server overload or process slowdowns. They handle requests independently, preventing application lock-ups during data transfers and requests.

Greater flexibility

Modern architectures and frameworks offer developers enhanced flexibility in developing applications. Through modular and extensible structures, developers can iterate rapidly and adapt to evolving circumstances, fostering more efficient development practices and delivering lasting value for investments.

Increased security

.NET Core's focus on the latest encryption standards ensures data privacy and security. Utilizing .NET Core's security protocols enables organizations to protect sensitive data and prevent unauthorized access and malicious attacks.

Expanded talent pool

.NET Core's open-source nature, cross-platform support, modularization, and high-performance capabilities attract more developers compared to .NET Framework. This broader interest in .NET Core expands the talent pool available for development projects.

Built-in cloud features

.NET Core includes built-in cloud features facilitating deployment in popular cloud environments such as Azure, AWS, and GCP. This provides scalability, flexibility, and access to advanced cloud-based services, ensuring reliable and secure deployments without compatibility issues.

Improved scalability

.NET Core enables running applications on multiple computers simultaneously, which is crucial for apps requiring additional computing power or websites experiencing heavy traffic. With fewer resources needed to run applications, more resources are available for processing requests, resulting in better scalability and reduced latency.

Seamless migration

Moving from .NET Framework to .NET Core can be achieved with minimal disruption to operations, especially when guided by a clear roadmap for future development. This migration process benefits from language compatibility and the ability to leverage familiar tools.

Advanced memory management

Finalizers free memory upon object deletion but may fail to execute smoothly. With .NET Core, finalizers are no longer a concern, eliminating potential memory management complications.

Although there's no immediate necessity to migrate from .NET Framework to .NET Core, it appears that the latter is the preferred framework for future development. If you're considering migration and lack an experienced in-house team, it's essential to seek out a company specializing in legacy software modernization and cloud services. This ensures a smooth transition and guarantees a seamless transfer of your applications. 

Technologies that are not supported by .NET Core

Several technologies are not supported by .NET Core, posing potential challenges during migration. It's crucial to focus on key components and tools throughout this process.

How to move from .NET Framework to .NET Core - Technologies that are not supported by .NET Core

Application domains

  • In .NET Core, application domains, which were previously used to isolate different applications within the same process, are no longer supported. Instead, consider utilizing the AssemblyLoadContext class for dynamically loading assemblies.


  • .NET Remoting, a technology facilitating inter-application communication, is not available in .NET Core due to the absence of application domains. Consider alternatives such as web services or other inter-process communication technologies like gRPC.

Code access security (CAS)

  • Code access security (CAS), a security feature in .NET Framework, is not supported by default in .NET Core. However, you can still manage permissions for assemblies through various options:some text
    • Implement role-based security for application security.
    • Utilize resource-based security for more granular control.
    • Employ an external authorization service for centralized authorization management.


  • LINQ to SQL, a .NET Framework component for managing relational data as objects, is not supported in .NET Core. Instead, consider using Entity Framework Core to achieve similar functionality, including support for transactions, views, and stored procedures.

By understanding the limitations and alternatives to these technologies, you can navigate the migration process more effectively and ensure a successful transition to .NET Core.

Steps to convert .NET Framework to .NET Core 

Once you decide to take the significant step to migrate from .NET Framework to .NET Core, you'll encounter two primary approaches: automatic and manual. Each approach offers distinct advantages and considerations, allowing you to tailor your migration strategy to best suit your specific needs and circumstances.

Automatic migration using .NET Upgrade Assistant 

For those seeking a streamlined migration process, the .NET Upgrade Assistant appears as a standout solution. This tool conducts a thorough analysis of your existing .NET Framework application, offering insightful suggestions and recommendations for transitioning to .NET Core. 

Not only does it identify compatibility challenges along the way, but it also generates a comprehensive report to serve as a valuable reference point throughout the migration journey. With the .NET Upgrade Assistant at your disposal, navigating the path to .NET Core becomes more efficient and manageable than ever before.

Manual migration 

When undertaking the manual migration process from .NET Framework to .NET Core, there are essential steps that you should adhere to.

There are certain steps you should adhere to when manually migrating from .NET Framework to .NET Core.

How to move from .NET Framework to .NET Core - Steps to migrate from .NET Framework to .NET Core
Step 1

Select the appropriate version

When selecting the right .NET Core version for your application, take into account factors like long-term support and feature availability. Don't automatically assume that the latest version is the best choice. Instead, evaluate the support level and the specific features provided by each edition. 

Step 2

Prepare your development environment

Download and install the .NET Core SDK, ensuring proper configuration of the development environment. The SDK equips you with essential tools and libraries necessary for application development.

Step 3

Initiate project creation

Start a new project within your selected development environment (Visual Studio). Opt for the suitable template that aligns with your migration objectives, like the ASP.NET Core Web Application template, to optimize the transition.

Step 4

Transfer code and dependencies

Move the files and dependencies from your existing project to the new one. Ensure to include any necessary NuGet packages and adjust your code to ensure compatibility with .NET Core.

Step 5

Update your NuGet packages

Migrate your NuGet packages by managing them in Visual Studio. Right-click on "References" and select "Manage NuGet Packages." 

Step 6

Move your data

For applications with databases, transfer the data to the new project. Visual Studio offers convenient "Export" and "Import" functionalities to facilitate this process. Additionally, you can utilize the "Generate Scripts" feature to create an SQL script for data migration.

Step 7

Update your .csproj file

Once you've migrated your code, dependencies, and data, proceed to transfer the .csproj file. Copy the file from your old project and make sure to adjust it to reference the new SDK correctly.

Step 8

Run testing 

After migrating your application to .NET Core, conduct comprehensive testing to confirm its proper functionality before deploying it for users.

Step 9

Deploy your app on .NET Core

Get your migrated app out there!

.NET Framework to .NET Core migration main challenges

Transitioning to .NET Core presents several challenges that need to be addressed:

Library compatibility

  • Certain libraries may not be accessible in .NET Core, prompting the need to identify and replace them with suitable alternatives. Moreover, implementing specific functionalities may require different strategies in the new environment.

API modifications

  • .NET Core brings about numerous modifications to the API in contrast to .NET Framework. Consequently, certain portions of the original application may require revision to align with the revamped API structure. 

Configuration and deployment

  • Configuration and deployment procedures may require adjustments to function optimally in .NET Core environments. This might involve modifying configuration settings, revising deployment scripts, and verifying compatibility with updated infrastructure.


  • Migrating from Framework to Core demands significant time and resources for testing, code refactoring, and adjustments. Prudent planning and resource allocation are imperative during the migration process.

How to prepare your system for .NET Framework to .NET Core migration?

.NET Core is known as a popular open-source, cross-platform, and high-performance framework for developing web applications. However, migrating from .NET Framework to .NET Core isn't a straightforward task. To ensure a successful transition, it's essential to navigate through the following steps diligently.

1. Evaluate compatibility with .NET Core : Use tools like the .NET Portability Analyzer to reveal if there are any unsupported APIs, libraries, or features, guiding necessary adjustments. 

2. Review API dependencies for potential replacements: .NET Core differs from .NET Framework. Refactor code to utilize compatible alternatives and prioritize cross-platform libraries for seamless integration.

3. Update third-party libraries: Ensure compatibility of 3rd party libraries with .NET Core. Update to compatible versions or explore alternative options if necessary. Contact library vendors for support if a compatible version is unavailable.

4. Develop a comprehensive test suite: Automated tests aid in detecting regressions or issues introduced during migration. Test critical paths carefully to validate system behavior.

5. Utilize .NET Core migration assistant to identify migration blockers and receive guidance on code updates: This tool automates parts of the migration process, saving time and effort.

6. Create a detailed migration plan: Outline steps, timelines, and potential risks. Prioritize critical components and consider phased migration to minimize disruptions. Ensure that team members and stakeholders communicate and coordinate effectively.

7. Thoroughly test the migrated system to ensure proper functionality: Validate critical functionality and stability before deploying to the production environment.

Your seamless migration from .NET Framework to .NET Core with TYMIQ

In wrapping up, transitioning from .NET Framework to .NET Core can be a daunting process, but it's certainly manageable. Understanding the migration principle and adhering to best practices are key to a successful transition, despite the hurdles encountered along the way.

Prior to start the migration, developers should meticulously prepare. This includes activities such as compatibility assessment, API review, library updates, test development, migration process planning, and system testing. By diligently following these steps, developers can smoothly transition their applications to .NET Core, leveraging its advanced capabilities to their fullest potential.

Should you require assistance with the migration journey, TYMIQ offers comprehensive services tailored to your needs. From initial assessment to meticulous planning and flawless execution, our team of engineers is equipped to guide you through the process. Trust TYMIQ to navigate any compatibility challenges and allow your application to thrive on the power of .NET Core.

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