Windows Update for Business and the retirement of SAC-T

Adam Sova Thank you for your explanation; it looks indeed I've been misunderstanding the deferral concept to the extent that I thought that the deferral period applied to the release date of the installed version (a new version will not be installed up until 365 days of release of the current verion) instead of the release date of the upcoming version (a new version will not be installed up until 365 days after that new version has been released)

Your explanation is the first that I'd call "human understandable" yet the problem for schools continues (if they don't build a clean image every summer based on the 03 version)

Taking back your example:

School did a clean 1803 install back in april or summer 2018 with deferral set to 365 meaning that the next version (1809) will not be installed up until 365 days after 1809 becomes available. So that effectively gives the school the possibility to use 1803 for 1 full schoolyear (sept 2018-june 2019) without feature upgrades happening during that schoolyear IF they build new images every summer based upon the 03 release.

If they don't build a new image every summer and just continue to use that 1803-please correct me if I'm wrong- then 1809 will be installed somewhere after november 12 2019 in the midst of the schoolyear; not acceptable. Next -if they continue to use that 1809- 1903 that was released march 2019 will be installed march 2020 again in the midst of the schoolyear.

So the next best thing to do for schools if not using the Enterprise LTSB/LTSC edition is to build a new image every summer using the then current 03 version.  That would avoid feature upgrades during the schoolyear.

I can now understand the 18 months suport period: in the example if 1803 was cleanly installed march 2018 it could be used up until september 2019 and that's 18 months.

I still wonder about the 30 months support for the 09 Enterprise & Education ( see https://support.microsoft.com/en-in/help/4462896/updates-to-servicing-and-support-for-windows-10) in relation to the 365 days deferrral; any idea what that could mean in human understandable language ? An example where a customer installs a clean Enterprise 1809 with deferral set to 365 (?) would help to understand!

LTSB/LTSC -imho- continues to shine because it should not be taken for granted that schools have the resources to build new images every year let alone to live through feature upgrade cycles twice a year. After all they've been used to work with an OS for say 5 year's in a row with all previous Windows versions... The OS is just a platform not a goal on it's own for most user's but MS seems to think different here.