Install new Exchange server
move the databases to the new server with database portability : https://technet.microsoft.com/EN-US/library/dd876926(v=exchg.150).aspx
Rename the old base that it reflects the new DB.edb before mounting.
recreate all connectors from the old server.
Create new certificate for the new server.
Change the DNS entry for the old server to point to IP address of the new server
Change Public folder homeMDB to point to the new PF database.This should be done on Publicfolder account in AD.
Remove the old server from Configuration name context in ADSI edit.under Servers OU and remove the databases which were on the old server from Database OU. Otherwise the DBs will not be shown in ECP and Shell.
Performed get-publicfolder -recurce | Add-PublicFolderClientPermission -User Anonymous -AccessRights CreateItems –so that mails can be send to PF