Let’s just dive into the changes in the console:
Recipients – Mailboxes
From the screenshots below, you can see that there is a change to the drop down when you click on the ‘…’ button.
Exchange 2013 RTM

Exchange 2013 RTM CU1

Now if you’ve used the RTM version of Exchange 2013, you will notice that the Disable mailbox option has been moved to the ‘…’ button instead of being a drop down off the Trash can icon. My guess is that this was done for ease of use and to prevent people from accidentally deleting mailboxes when all they want to do is disable a mailbox.
Recipients – Groups
The change to the options or ‘…’ menu are merely cosmetic on this tab.
Exchange 2013 RTM
Exchange 2013 RTM CU1
Recipients – Resources
The change to the options or ‘…’ menu are also cosmetic on this tab.
Exchange 2013 RTM
Exchange 2013 RTM CU1
Recipients – Resources
The change to the options or ‘…’ menu are again cosmetic on this tab.
Exchange 2013 RTM
Exchange 2013 RTM CU1
Permissions – Outlook Web App
when configuring a new OWA policy a couple of options under Information Management have been removed from the RTM version of the policies. Specifically Search Folders and Public Folders.
Exchange 2013 RTM
Exchange 2013 RTM CU1
Compliance Management – Auditing
If you were to run a new Admin Role Group report in CU1, you would notice that the screen is organized a bit different than it was in the RTM version of Exchange. Now the date range is logically put at the top and the search results are at the bottom.
Exchange 2013 RTM
Exchange 2013 RTM CU1
Protection – Malware Filter
The Malware Filter has also been tinkered with in the CU1 release of Exchange 2013. It looks like Microsoft is locking down on the configuration options of this feature in Exchange. You can no longer remove or create new Malware Filters. The only option is to work with the Default Policy that is present when Exchange is installed.
Exchange 2013 RTM
Exchange 2013 RTM CU1
The changes are also visible in PowerShell as you can see that the commands related to removing or creating a new Malware Policy are gone.
Exchange 2013 RTM
Exchange 2013 RTM CU1
There might be a fourth article if I find enough material to post on other changes in Exchange Server 2013 RTM CU1. Thanks for reading the article.