The Sage CRM .NET API is based on the .Net Framework, not the .NET Core.
Microsoft confirms support for the underlying .NET Framework until 9th January 2029.
The Microsoft .NET Framework is a proprietary environment for building, deploying, and running Web Services and other applications. It consists of three main parts: the Common Language Runtime, the Framework classes, and ASP.NET.
.NET Framework provides a large body of pre-coded solutions to common program requirements and manages the execution of programs written specifically for the framework.
The Sage CRM .NET API provides a type library that exposes the Sage CRM objects, properties, and methods. Through its core libraries, the Sage CRM .NET Component manages both data access and web interface generation. Projects developed using the Sage CRM .NET Component will be compiled into a dll and called directly from within Sage CRM. By using Sage CRM metadata Application Extensions constructed using the Sage CRM .NET API will look, feel and perform exactly like core system pages.
Note: Microsoft .NET Core is a free, open-source, general-purpose development platform to build cloud-based software applications on Windows, Linux, and macOS whereas Microsoft’s .Net Framework is a software development platform for building and running Windows applications.
Background:
Sage CRM .NET API conforms to Microsoft .NET Framework 2.0
https://help.sagecrm.com/on_premise/en/2022R2/Dev/Content/Developer/DN_ExtendingCRMWithDotNET.htm
.NET Framework is defined as a component of the Windows operating system (OS). Components receive the same support as their parent products.
See: https://learn.microsoft.com/en-US/lifecycle/faq/dotnet-framework
The .NET Framework 3.5, the .NET Framework 3.0, and the .NET Framework 2.0 were historically released as individual products on platforms in versions of Windows earlier than Windows 7 and Windows Server 2008 R2.
Each of these product versions is really a layer of a feature stack. Internally, each layer contains mutually exclusive components. So, components in the .NET Framework 3.0 build on top of the .NET Framework 2.0, and components in the .NET Framework 3.5 build on top of both the .NET Framework 2.0 and the .NET Framework 3.0.
" .NET Framework 3.5 cannot function without the .NET Framework 2.0 and the .NET Framework 3.0 because there is no common language runtime (CLR) in the .NET Framework 3.5 layer. "
Because the .NET Framework 3.5, the .NET Framework 3.0, and the .NET Framework 2.0 were released as independent product versions, each of these products has independent support lifecycles.
Microsoft will provide support for the .NET Framework 2.0 and .NET Framework 3.0 components for customers who install the .NET Framework 3.5 for as long as the .NET Framework 3.5 remains in support.
.NET Framework 3.5 SP1, beginning with Windows 10 version 1809 and Windows Server 2019, is a standalone product and receives 5 years of mainstream support followed by 5 years of extended support. For operating systems released before Windows 10 version 1809 and Windows Server 2019, .NET 3.5 SP1 remains a component of the Windows version on which it is installed.
https://learn.microsoft.com/en-US/lifecycle/faq/dotnet-framework
This means that support for the .NET Framework 3.5 Service Pack 1 will end on 9th January 2029.
https://learn.microsoft.com/en-us/lifecycle/products/microsoft-net-framework
This article applies to Sage CRM stand-alone and when integrated with Sage accounting products. Sage 50, Sage 100, Sage 200, Sage 300, Sage X3 and Sage Intacct.