Bruce Greene wrote:
My question is - how important is it that I drop
You have two customer bases 1. Existing 2. New For both types of customers do they buy new hardware? How often do they upgrade windows? Leaving it as is runs the risk of, at some point, your software will fail in some odd way or not run at all because of updates to windows. However updating also runs the risk that will not run on older versions either. These days older apps also have an increased security risk. Or at least it is perceived that way. So it is possible at some point that something (like a virus checker) might flag the app for something. Which makes customers nervous. You might also want to validate how exactly your build process works. If you are expecting to be able to download libraries (specific versions) any time you want at some point that might no longer be possible. You can address that keeping the libraries in your own source control and download nothing. Besides the customers the primary way is to look for "end of life" for anything. Could be operating system, libraries, hardware etc. For the version you specified above the date is April 26, 2022. It is unlikely anything will fail now. But you probably don't want to still be waiting 5 years from now. Microsoft .NET Framework - Microsoft Lifecycle | Microsoft Learn[^] If you have customers that do not upgrade then you will also need to plan on continuing supporting them. Note that this also means that you will need to have hardware and operating system that you can both test on and develop on. Keeping in mind however that even if it is good money maker at some point even they will find it difficult to keep running with the old equipment. Although some people are very ingenious at finding sources.
