Microsoft plans to post notices in OWA to tell end users that their Office 365 licenses include Outlook Mobile. The hope is that more people will use Outlook Mobile instead of EAS or IMAP4-based clients like the default iOS mail client. Notices will appear in OWA and later Outlook desktop, but the good news is that you can disable these notices with a simple change to the tenant’s organization configuration for Exchange Online.
Changes coming in May and June will allow organizations to make online meetings the norm when created by OWA or Outlook mobile clients. You can control the feature at the organization level and allow individual mailboxes to override the organization setting.
Microsoft plans to disable basic authentication for five Exchange Online connection protocols on October 13, 2020. They’ve been clear on this point for several months and are now moving to deliver tools and provide guidance about what people should do about clients that use basic auth connections with Exchange Web Services, Exchange ActiveSync, IMAP4, POP3, and Remote PowerShell. Work is needed to make sure that clients are prepared for the switchover to modern authentication.
A recent update for Exchange Online gives extra control over who can access public folders. The change is intended to help with scalability, but it can be used to turn public folders off for any mailbox for which you care to disable access.