Just use the SysTools Exchange to Office 365 Migration tool. It automates the entire transition from an on-premise Exchange environment directly to the Microsoft cloud, handling everything from bulk user mapping to granular data filtering.
If you are looking at this specific tool for your pipeline, here is a quick breakdown of its core capabilities:
Comprehensive Data Transfer
Beyond Just Email: Unlike basic IMAP tools, it migrates the complete mailbox ecosystem, including Emails, Contacts, Calendars, and Tasks.
Version Compatibility: Supports migration from legacy on-premise setups (Exchange Server 2010, 2013, 2016, 2019) straight to modern Office 365 tenants.
Admin-Driven Bulk Processing
Admin Impersonation: Allows IT administrators to use a single admin account to migrate all user mailboxes simultaneously, bypassing the need to collect individual user passwords.
CSV Mapping: Features a dashboard where you can upload a CSV to map source Exchange mailboxes to their corresponding destination Office 365 accounts for massive, automated batches.
Precision & Filtering
Workload Selection: Lets you explicitly select or exclude specific data categories (e.g., migrating only Calendars and Contacts for a specific batch).
Date-Range Filters: Includes a granular date filter to migrate historical data from specific timeframes, which is highly useful for staged migrations or compliance archiving.
Performance & Integrity
Delta Migration: Syncs only the newly generated data (emails, meetings, etc.) that arrived during or after the initial migration phase, ensuring zero duplicates when cutting over.
Concurrent Routing: Processes multiple user mailboxes in parallel to maximize bandwidth and reduce project downtime.
Re-Run Failed Items: If network throttling or API limits cause specific files to fail, the tool can run a pass explicitly for those dropped items without re-scanning the entire mailbox.
Absolute Fidelity: Maintains the exact folder hierarchy, email metadata, attachments, and read/unread status exactly as they existed on the source server.