Rather than using SPRING or FALL ‘seasonal’ naming conventions for WIN10 upgrades, “Windows 10 April 2018 Update” will reflect the new official name of WIN10 v1803. The previous update approach may have even been confusing to some users in southern hemisphere, where seasonal patterns are opposite.  A month/year approach will share the approximate timing of when release is finalized & available for distribution  

https://www.computerworld.com/article/3269292/microsoft-windows/why-microsoft-gave-windows-10-version-1803-a-different-name.html

Microsoft will start distributing the next Windows 10 feature upgrade, “Windows 10 April 2018 Update” today – a few weeks later then it had been expected to arrive.

The release date barely squeaked under the wire Microsoft set for itself with its labeling of the upgrade, although the company has never expressed concern when actual release dates have conflicted with each update’s alternate – and numeric – title, the one formatted as yymm. That conflict continued with the April 2018 upgrade. Its 1803 moniker envisioned a March, not a last-day-of-April, debut.

Microsoft fell back on the in-place date naming – From the first year of Windows 10, Microsoft has used yymm as another, and shorter, name for each feature upgrade, including 1507 (the original), 1511 (the first upgrade of November 2015), 1607, 1703 and 1709 (released in October 2017).

Microsoft at least makes it easier to remember when an upgrade debuted. And that’s important, since each upgrade is supported for a limited time: 18 months for Windows 10 Home and Windows 10 Pro, 24 months for Windows 10 Enterprise and Windows 10 Education.  However, Microsoft may have just confused matters with the month,year. Unless the former 1803 designation is changed (to 1804), the two do not match. Which is the one used for starting the support count?