Exchange 2010 to Exchange 2016 High level migration Check List for Specialists.
– SSL Certificate Planning (Wild Card or SAN Certificate is in use make sure all primary domain have auto discover entries in the the new Exchange 2016 Servers.)
– Exchange 2016 Sizing as per Microsoft Recommendations.
– Usage of Load Balancer. (one arm / two arm configurations) Set expectations on visibility of email / client source IP. X-Forwarder.
– Usage of a WAF / Reverse proxy solution . (For Better Security )
– Check Proxy Settings like use of PAC file or ISA or Zscaler. See Outlook Connectivity with test DNS. As host file will not take effect to test client connectivity in the time of client access cutover.
– Check MX Record on where its pointing and check how it can moved properly to Exchange 2016 Servers via Anti-spam solutions.
– Remove Public Folder Database Attribute . if you don’t wish to use public folders . As outlook connectivity will break for exchange 2016 when outlook tries to connect to Exchange 2016 and another request will try to connect exchange 2010 public folders. breaking the outlook connectivity.
– While moving mailboxes . Make sure auto discover recycle pool is recycled frequently once the move completes. So that outlook will reconnect quickly.
– Once you Install new exchange servers make sure autodiscoverinternaluri is changed via set-clientclientaccessserver so that outlook in the environment will not get any surprise cert error prompts.
– Make sure additional softwares are implemented properly like signature software’s / Email Archiving / Backup.
– Make sure email relaying connectors or copies to the new servers using PowerShell.
– Make sure anti virus exclusions are set properly on the new servers.
– Make sure send connectors are updated properly before you shutdown and uninstall Exchange 2010 servers..
Please feel free to add in comments. I can update the same.