Windows 10 Expired Releases

Solution 1:

To my knowledge the answer is no, these old releases are no longer receiving updates after their expiration date.

See also this article about expired Windows 10 versions (general, not specific to Enterprise and Education):

We recommend updating all of these earlier versions to the Windows 10, version 20H2 to continue receiving security and quality updates, ensuring protection from the latest security threats.

Windows 10, version 1507, 1511, 1607, 1703, 1709, and 1803 are currently at end of service. This means that devices running these operating systems no longer receive the monthly security and quality updates that contain protection from the latest security threats.

To my knowledge the exceptions to the expectation to upgrade to the new releases in a somewhat timely fashion are the long-term support versions (LTSB/LTSC), like Windows 10 2016 LTSB and 2019 LTSC.
(Essentially long-term support versions for the desktop based on the same Windows codebases as Windows Server 2016 and 2019).