Each update is deployed as part of a Release Train, stopping at each ‘station’ along the way before rolling on to subsequent station. Not all regions would be on the same release as any time. Early station will have lower levels of number of customers impacted, ending with Europe and North America where majority of our customers are and then dedicated scale groups where customers with larger organisations are hosted. For a more in-depth session on this topic I can highly recommend the recording BRK2039 - Microsoft PowerApps and Dynamics 365: Modernizing the way we update
In November 2019 Microsoft updated their documentation and provides a lot more transparency on this release process - so you can now get a full overview of Released Versions of Dynamics 365 for Customer Engagement which outlines all previous releases as well as the upcoming releases in the different stations.
The version number mechanism for Dynamics 365 CE instances has also been updated so it is now easier to see which update has already been rolled out to a specific instance.
