If there isn't any Product Administration(ABQ) policies applied OR cellular sharing is disabled for ActiveSync people, you are able to skip the ways to export/import the cell information. Following the accounts are migrated to Zimbra Daffodil (v10) server as per Migration of accounts portion, import the Cell knowledge using the https://alexisylwgq.wikibuysell.com/764349/details_fiction_and_zimbra_migration_service