I did a session at TechEd New Zealand a few weeks ago talking about what’s changed in MDT 2013.  As part of that session, I put together a list of all the changes in the MDT 2013 release, comparing all the scripts and configuration files, looking through all the bugs fixed, etc.  Since that information might be useful to others (at minimum to convince people that this is a rather low-risk upgrade if you are deploying Windows 7 and above and using ConfigMgr 2012 R2), the list is included below.

Scripts

DeployWiz_LanguageUI.xml. Fixed Brazilian Portugese keyboard layout references.

LTIApply.wsf. Fixed issues with UEFI x86 and UEFI prestaged media deployments.

InternationalSettings.xml. Fixed Russian Standard Time text to correctly indicate UTC+04:00.

OSDBranding(x64).vbs. Added logic to ensure only app variables are branded to the registry.

ServerManager.xml. Updated role list to add Windows 8.1 and Windows Server 2012 R2 roles and features, removed entries for OSes that are no longer supported.

ZTIDataAccess.vbs. Modified logic to try all ConfigMgr R2 network access accounts.

ZTIExecuteRunbook.vbs. Modified logic to try all ConfigMgr R2 network access accounts.

ZTIOSRole.wsf. Added logic to install Windows 8.1 and Windows Server 2012 R2 roles and features.

ZTIPSUtility.vbs. Modified logic to handle new PowerShell versions.

ZTISupportedPlatforms.xml. Modified to match OS versions supported by MDT 2013.

ZTIUtility.vbs. Modified logic to try all ConfigMgr R2 network access accounts.

Task sequence templates

SCCM_Client.xml, SCCM_Server.xml. Fixed UEFI format steps to set OSDTemporaryDrive and OSDisk variables, removed Windows XP/Server 2003 format steps.

Other files

BDDAdminDB.sql. Modified the application field name to allow for names up to 255 characters.

Unattend_(x86/x64).xml. Removed IE welcome page setting, added replacement IE settings.

GPO packs. Removed all the GPO packs.

Bug fixes

Fixed error while updating winpeshl.ini when DaRT is included in boot images.

Fixed issue with locating DaRT remote control viewer.

Removed ConfigMgr 2007 from integration wizard.

That’s the list.  If a particular script file isn’t listed, it hasn’t changed (except for the version number).  There were some other behind-the-scenes changes (e.g. to support ADK for Windows 8.1), but you won’t notice those.

Remember that MDT 2013 only supports deployment of WIndows 7 or above, using ADK for Windows 8.1 only, and doesn’t support any version of ConfigMgr prior to 2012 R2.  If you are still deploying Windows XP or Windows Vista, or using ConfigMgr 2007 or 2012 SP1, keep using MDT 2012 Update 1, which is still supported.

Also, be sure to read the list of known issues in the release notes.