We have two different forests.
Forest 1 = domainA.local
Forest 2 = domainB.com
These are two separate forests but there is a trust between the two of them in order to allow access to certain systems and services on the domainB.com network. There is also a Site to Site VPN between the two locations. You can see the entire directory in the attached image.
domainB.com has all domain controllers with 2008 R2. domainA.local has 2003 Domain Controllers. The forest level of domainB.com has been left at 2003 due to not knowing if raising the forest level will affect the trust in any way.
Is it safe to say I can raise the function level of the domainB.com trust to 2008 R2 without affecting the domainA.local domain. I would like to take advantage of other features in a 2008 R2 domain level.
Any assistance is appreciated.