One option is to upgrade the add-ins to a more recent version of the VSTO Runtime. Visual Studio 2012 and later versions introduced updated runtimes that offer better compatibility with modern Office versions and are still within their respective support windows. This is often the quickest fix for internal developers who want to maintain the existing C# or VB.NET code base.
Because the runtime is EOL, Microsoft will not issue a fix. The business is now stuck: upgrade the OS and lose the add-in, or keep the OS outdated and lose security compliance. visual studio 2010 tools for office runtime end of life
The end of life for Visual Studio 2010 Tools for Office Runtime marks the end of an era for developers who have built custom solutions for Microsoft Office using this technology. While it presents challenges, it also offers opportunities for developers to modernize their solutions, adopt newer technologies, and benefit from improved security, scalability, and maintainability. By understanding the implications and exploring alternatives, developers and users can ensure the continued success and security of their Office solutions. One option is to upgrade the add-ins to