Microsoft 365 Roadmap
A new capability called Auto-Archiving for Exchange Online will enter public preview in November 2025 (currently under private preview for selected customers). When a user's mailbox utilization exceeds 95% of its quota and archive mailbox is present, this feature automatically moves the oldest items excluding those tagged with “Never Move to Archive” from the primary mailbox to the archive mailbox to prevent mail flow disruptions by keeping usage below the safe threshold of 95% of mailbox quota.