my company has exchange 2007 hub and edge and exchange 2010. I'm planning to retire all exchange 2007 first follow migrate to exchange 2013. so I have few questions as below ?
1. Do I need to unsubscribe hub 2007 from edge first before uninstall ? Currently we have 2 hubs (2007 and 2010). How can I remove hub 2007 from exchange edge server 2007 ?
2. let say once my landscape just have exchange 2010, is it installing our first exchange 2013 will impact our mail flow ? my understand there is NO impact until we switch over 'mail IP' to CAS 2013. am I correct ?
3. what is minimum requirement for co-exist with exchange 2013 for exchange 2010 ? is it enough with SP3 or I need to apply SP3 RU5 ? in deployment assistant, the requirement is SP3 RU5 but most article i read just mention SP3.
thx.