Из другой темы, но здесь более уместно (спасибо TRUD)
Since Platform update 3, Microsoft has been committed to backward compatibility in the cloud platform
for Finance and Operations and has removed the capability to make intrusive customizations in the platform.
Microsoft will continue to work closely with you to help guarantee that your environments are updated and current. Starting in July 2018, all customer environments will be continuously updated
and kept current on the latest version.
A planned maintenance window
is the timeframe that Microsoft has scheduled to apply critical updates to your cloud service.
Operating system–level updates are completed in approximately one hour.
Platform updates are typically completed in one to three hours. In rare instances, a platform update can take up to eight hours to be completed.
The exact downtime for all updates will be included in the maintenance window notification email
that is sent to you before the start of the update.
Platform updates are applied on the Tier-2 sandbox environment that is included in the Microsoft base offer. After validating that the environments are patched successfully, Microsoft will apply this update in the production environment within five days.
You will receive an email notification five days before the update is scheduled to occur
. This notification will include information about the environments that will be updated, the update type, the estimated amount of time that the update will take, and any action that you may have to take.
We do not offer an option to reschedule a planned maintenance.
However, you can select to be excluded from the maintenance cycle for the current month. We plan to add this option into LCS so that you can reschedule an update directly through LCS.
To opt out of the current maintenance cycle, file a support ticket with Microsoft. Your environment will be excluded from the maintenance cycle for the current month. However, your environment will be updated the next month.