The most suitable replacement will be Windows 10 21H2, the refresh released in October 2021 that also offered two-and-a-half years of support.

Is there coming a Windows 11?

Microsoft has announced that Windows 11 is going to be available for new machines starting October 5, 2021. Updates to existing Windows 10 users should start coming at the start of 2022, and Microsoft hopes to have offered Windows 11 to every compatible machine by mid-2022.

What is Microsoft replacing Windows 10 with?

Just before Microsoft released Windows 10, an employee said the operating system would be the last version of Windows. Some people expect Microsoft to introduce Windows 11, though. There are good reasons for Microsoft to roll out a major update, rather than another incremental enhancement to Windows 10.