According to MacRumors, Microsoft today began disabling Exchange Web Services (EWS) by default in Exchange Online. It is the protocol that Apple Mail and Calendar on Mac still rely on to sync Microsoft 365 work accounts, so syncing could stop working.
This is a single-source report. Details on exactly who is affected and what users can do are in the original article.
For system updates, the important distinction is whether Apple has released a stable version or is still testing a beta. AppDrop therefore shows the original source and publication date. Before installing a major update, check device compatibility, availability for your Apple account and keep a current backup of important data.
Rollouts can arrive gradually and availability may vary by device or region. If the story concerns a beta release, remember that beta software is intended for testing and can contain bugs; a stable release is usually the safer option for a device you depend on every day.