Domain Level Windows Server 2012 R2
Domain functional level dfl determines the features of a domain controller dc based on the windows server operating system os it runs on.
Domain level windows server 2012 r2. It depends on the following factors whether or not a domain can add a w2012r2 domain controller. The forest functional level has to be at least w2003. Prequesitions for adding a windows server 2012 r2 to the domain. If you are going to raise functional levels to 2012 r2 all your domain controller must be running windows 2012 r2.
Today i recognized that it is not easy to find a comprehensive summary table about active directory domain and forest functional levels operating mode on the internet. Feature set of a particular dfl will be available for a dc if it runs on the operating system version that is compatible with the functional level. Since it looks like you still have a 2008 domain controller you must either upgrade it to 2012 r2 decommission it or stay at 2008r2 functional level. A new domain that is created on a domain controller that runs at least windows server 2012 r2 must be set to the windows server 2008 domain functional level or higher.
Domain based dfs namespaces running in windows server 2008 mode which includes support for access based enumeration and increased scalability. You can configure a windows server 2012 r2 server to host a domain and when the configuration completes the server is called a domain controller. A domain controller serves many purposes but is used primarily for user logon management organization through security groups and centralized management of policies and properties on computers. If you are planning to deploy dc then select windows server 2008 or windows server 2008 r2 as forest and domain functional levels.
The domain functional level has to be at least w2003. Take a look at the article below for more info. The domain has to be ready. The forest scheme has to be ready for w2012r2.
There are some explanations with the functions up to windows server 2008 r2 and some on the differences between windows server 2008 r2 and windows server 2012.