Microsoft 365 contact details do not contain the Middle Name or Middle Initial field. Furthermore, the Middle Initial Field is a field automatically synced by Azure AD by default (dirsync).

CiraSync has recently introduced a new feature for users who want to sync the Middle Name/Initial field. This is done by mapping the initial field in the GAL to the Middle Name/Initial field. To start syncing the Middle Name/Initial field to your users, do the following:

1. Log in to the CiraSync dashboard.
2. Click the username/display name in the top-right corner of the window.
3. Click Settings. CiraSync settings will open.
4. Click Contact Fields. The Contact Field settings will open.
5. Scroll to the bottom of the window.
6. Check the Map GAL Initials to Middle Name attribute box.
7. Click SAVE in the top-right corner of the window.