It's also possible that Win7/8 users won't even notice and continue to use it, and receive updates. I don't think the Steam client has separate builds for diffe

It's also possible that Win7/8 users won't even notice and continue to use it, and receive updates. I don't think the Steam client has separate builds for different Windows versions, dropping support can mean many things. - Blocking access from Win7/8 entirely, for any installed version of the client on Win7/8. - Staying on last client version which may or may not continue to work with the server. - Losing the ability to receive oncall customer support if the software is not working properly, but continuing to get updates that may or may not work with your old system, and maybe slowly losing features, including potential security issues. I'm still using my Google Pixel 3 phone, Google has dropped support in oct 22, so no new Android versions or security updates for me, but it runs fine and I'm not planning to replace it anytime soon. If it breaks or leaks my data, I won't complain to anyone. Of course, client-server software is an entirely different thing, but you get the idea. End of support notices are always incredibly vague, because the software vendors don't want to make customers who won't upgrade their devices angry without a valid reason, so often they won't cut access if there's no big security issue, but they also don't want to tell everyone that it's still probably ok to continue using the old versions, because moving on brings performance improvements which are good for users and maintaining old software becomes increasingly difficult over time.