Mail delivery.
If you are implementing coexistence, you must plan where incoming mail will be delivered. Delivery will initially be to the onpremisesserver, but you will need to determine if this is the best long-term arrangement in a coexistence scenario. You must also identify the point at which you will switch over in a cutover or stagedmigration.
Domain name services (DNS) settings.You will need to plan for DNS configuration changes during the
migration process, such as MX records, CNAMES, and Autodiscover settings. Remember that DNS
settings can take a while to propagate globally and that changing the Time to Live (TTL) setting can
help speed up this process.
Communications.It is essential that you communicate relevant and timely information about the
migration plan to users. The pilot users can help assure people that the migration should go
smoothly, but you must not overlook this factor in your planning.
Training.If your organization’s users are moving from one mail client to Outlook 2013 they will
require a significant amount of training on this new client. If they are updating from an earlier version
of Outlook this training requirement will be diminished, but you must still ensure that you have
covered training as a consideration in your plan.
File types.SharePoint Online blocks some file types. Ensure your users appreciate the implications of
these blocked file types.