Microsoft has recently released (2/12/2013) Service Pack 3 (SP3) for Exchange Server 2010 which required to co-exist and upgrade for Exchange Server 2013. You can download it from below link.
This Exchange Server 2010 SP3 software may be used to perform a new installation or to update an existing Exchange Server 2010 installation to Service Pack 2 (SP2) level. Make sure to get a full backup prior to install the Service pack.
This Service Pack includes the following new features and capabilities:
- Coexistence with Exchange 2013: You can now install Exchange Server 2013 in your existing Exchange Server 2010 organization. To do this, install Exchange Server 2013 Cumulative Update 1 (CU1). You cannot install Exchange Server 2013 in your existing Exchange Server 2010 organization by using Exchange Server 2013 RTM installation media.
Note Exchange Server 2013 CU1 is also an installation medium for Exchange Server 2013.
- Support for Windows Server 2012: You can now install and deploy Exchange Server 2010 on computers that are running Windows Server 2012.
- Support for Internet Explorer 10: You can now use Internet Explorer 10 to connect to Exchange 2010.
- Customer Requested Fixes: Exchange Server 2010 SP3 contains all the fixes that are contained in update rollups that were released before SP3. For more information about the release schedules of Exchange 2010 updates
- Client Access Servers
- Hub / Edge Servers
- Mailbox Servers
- Unified Messaging Servers
And there is an optional prerequisites hotfix also. You can download it from below link.
Restart the Server and start the upgrade.
Click Install Microsoft Exchange Server Upgrade
Accept Terms and Conditions.
Readiness Checks. Click Upgrade.