The version of your site after upgrading to System Center 2012 Configuration Manager SP2 depends on the pre-upgrade version:
- System Center 2012 R2 Configuration Manager: After installing service pack 2 your new site version will automatically update to System Center 2012 R2 Configuration Manager SP1.
- System Center 2012 Configuration Manager SP1: After installing service pack 2 your new site version will be System Center 2012 Configuration Manager SP2.
Here is relative Checklist to follow:
Here they are some of them:
- Each site in the hierarchy must run the same version of Configuration Manager prior to beginning the upgrade. This is either System Center 2012 Configuration Manager SP1 or System Center 2012 R2 Configuration Manager.
The version of cumulative updates for Configuration Manager that are installed a site is not evaluated, and does not affect the upgrade process or success. - Before you upgrade a site, you must resolve all operational issues for the site server, the site database server, and site system roles that are installed on remote computers. A site upgrade can fail due to existing operational problems.
- Before you upgrade a site, install any critical updates for each applicable site system. If an update that you install requires a restart, restart the applicable computers before you start the upgrade.
- Disable database replicas for management points at primary sites.
For more information, see Configure Database Replicas for Management Points. - Before you upgrade a site, back up the site database to ensure that you have a successful backup to use for disaster recovery. https://technet.microsoft.com/en-us/library/gg712697.aspx
- Before you upgrade the version of a Configuration Manager site, disable any site maintenance task that might run at that site during the time the upgrade process is active. This includes but is not limited to the following:
- Backup Site Server
- Delete Aged Client Operations
- Delete Aged Discovery Data
When a site database maintenance task runs during the upgrade process, the site upgrade can fail.
Before you disable a task, record the schedule of the task so you can restore its configuration after the site upgrade completes. - Starting at the top-level site in the hierarchy, run Setup.exe from the System Center 2012 Configuration Manager SP2 source media. After the top-level site completes the upgrade and replication is Active, you can begin the upgrade of each child site. Complete the upgrade of each site before you begin to upgrade the next site.
Until all sites in your hierarchy upgrade to the new product version, your hierarchy operates in a mixed version mode. - If you use database replicas for management points at primary sites, you must uninstall the database replicas before you upgrade the site. After you upgrade a primary site, reconfigure the database replica for management points.
- If you disabled database maintenance tasks at a site prior to the upgrade, reconfigure those tasks at the site using the same settings that were in place prior to the upgrade.
- After you upgrade a primary site, plan to upgrade clients that are assigned to that site. Although a Configuration Manager primary site or secondary site can support communication from clients that have a lower service pack version, this communication should be a temporary configuration. Clients that run a previous version of Configuration Manager cannot use the new functionality that is available with the new version of Configuration Manager.
After upgrade and manual actions to do:
- After the site upgrades, you must manually upgrade physical media like ISO files for CDs and DVDs or USB flash drives, or prestaged media used for Windows To Go deployments or provided to hardware vendors. Although the site upgrade updates the default boot images it cannot upgrade these media files or devices used external to Configuration Manager.
- Plan to update non-default boot images when you do not require the original (older) version of Windows PE.
Here they are resetting settings that happen after upgrade proces:
- When you upgrade to System Center 2012 R2 Configuration Manager, the following Software Center items are reset to their default values:
- Work information is reset to business hours from 5.00am to 10.00pm Monday to Friday.
- The value for Computer maintenance is set to Suspend Software Center activities when my computer is in presentation mode.
- The value for Remote control is set to the value in the client settings that are assigned to the computer.
[original Microsoft Article https://technet.microsoft.com/en-us/library/jj822981.aspx]