Windows Operating Systems Life Cycle Details
Microsoft’s product life cycle/support is fairly simple but they do a good job of making it look complicated and annoying to gather all the information.
There’s usually 2 dates of importance: mainstream support, and extended support end dates.
Mainstream is basically all the new features / improvements and standard non-security focused updates.
Extended support begins after Mainstream, and ensures the continuation of security patches.
They also throw in the dates of service packs but you can generally base yourself on the “Extended Support” date as your deadline for migrating to a newer system.
Your systems will still work perfectly fine past these dates, this is mainly a security issue as there will no longer be patches for any issues found. In the case of completely isolated systems this is not a huge deal, but for anything connected to a network or that has user interaction it can be a nightmare waiting to happen. Did you know that as of early 2016, many bank terminals/ATM systems still run on Windows XP? Let that sink in for a minute.