We are looking into upgrading our AD to 2012 R2 functional level to start planning 2013 migration from 2010 However, we still have some exchange 2007 servers that will be around for few more months. Is exchange 2007 supported in a Forrest with windows 2012 R2 functional level?

You don't need to go right to 2012 R2 functional levels for Exchange 2013. Here's an article that explains the various minimum requirements for Exchange 2013: http://social.technet.microsoft.com/wiki/contents/articles/14333.minimum-system-requirements-and-forest-functional-level-for-exchange-201

We don't but our infrastructure group would like to go to 2012 R2 functional level for other reasons. We are planning ahead for either situation with or without 2012 functional level. The question I have is: If we can have exchange 2007 in a windows 2012 R2 functional level forest, what is the minimum RU that needs to be installed on it?

Assuming you'll be installing a recent build of Exchange 2013 (at least SP1 (RU4) or higher), the minimum requirement for coexistence with Exchange 2007 requires 'Update Rollup 10 for Exchange 2007 SP3 on all Exchange 2007 servers in the organization, including Edge Transport servers'.  I'm not currently finding TechNet documentation speaking of functional level 2012 R2 in relation to Exchange 2007.  Here's some documentation to read:

https://technet.microsoft.com/en-us/library/jj898581(v=exchg.150).aspx

https://technet.microsoft.com/en-us/library/ff805032(v=exchg.150).aspx

Thanks. I am familiar with the minimum requirement for coexistence between Exchange 2007 and 2013. I still can not find a written documentation that says " if you are planning on running exchange 2007 in a 2012 R2 functional level Forrest then the minimum you need is this ..." etc

Ok, just found it; according to the article below, even with Exchange 2007 SP3 with Rollup 13, 2012 R2 forest/domain functional level is NOT supported.  You can have a 2012 forest/domain functional level.  You CAN have 2012 R2 DCs though.

https://technet.microsoft.com/en-us/library/ff728623%28v=exchg.150%29.aspx?f=255&MSPPError=-21472173

Thanks. I missed that one for some reason. I was hoping they would change that with the latest Roll up.

Microsoft,

Any plans to support that scenario? We have some third party vendors that are dragging their feet to up date their code so we are stuck with Exchange 2007 for a little bit longer.

• Edited by Mike Logan 15 hours 10 minutes ago

just upgrade from 2012 FFL/DFL to 2012R2 FFL/DFL after you have removed Exchagne 2007 envirinment. There are no new features when you upgrade your FFL from 2012 to 2012R2. There are however minor changes when you upgrade your DFL from 2012 to 2012R2.

See the link below for all of the details.

https://technet.microsoft.com/en-ca/library/understanding-active-directory-functional-levels(v=ws.10).aspx

Will.

• Edited by Will Szymkowski- 14 hours 52 minutes ago

just upgrade from 2012 FFL/DFL to 2012R2 FFL/DFL after you have removed Exchagne 2007 envirinment. There are no new features when you upgrade your FFL from 2012 to 2012R2. There are however minor changes when you upgrade your DFL from 2012 to 2012R2.

See the link below for all of the details.

https://technet.microsoft.com/en-ca/library/understanding-active-directory-functional-levels(v=ws.10).aspx

Will.

I think that's why Mike means by "so we are stuck with Exchange 2007 for a little bit longer."

Yeah... and i was pointing out that there are not many differences between 2012 and 2012R2 FFL/DFL anyways.

Will.

Thanks. I missed that one for some reason. I was hoping they would change that with the latest Roll up.

Microsoft,

Any plans to support that scenario? We have some third party vendors that are dragging their feet to up date their code so we are stuck with Exchange 2007 for a little bit longer.

• Edited by Mike Logan Friday, August 07, 2015 4:20 PM

just upgrade from 2012 FFL/DFL to 2012R2 FFL/DFL after you have removed Exchagne 2007 envirinment. There are no new features when you upgrade your FFL from 2012 to 2012R2. There are however minor changes when you upgrade your DFL from 2012 to 2012R2.

See the link below for all of the details.

https://technet.microsoft.com/en-ca/library/understanding-active-directory-functional-levels(v=ws.10).aspx

Will.

• Edited by Will Szymkowski- Friday, August 07, 2015 4:39 PM

Thanks. I missed that one for some reason. I was hoping they would change that with the latest Roll up.

Microsoft,

Any plans to support that scenario? We have some third party vendors that are dragging their feet to up date their code so we are stuck with Exchange 2007 for a little bit longer.

While i don't work for Microsoft, I highly doubt that they have any plans on supporting a Windows Server 2012R2 forest and domain functional level in Exchange 2007.  Exchange 2013 started supporting this when SP1 was released last April.  If they were going to make this change with Exchange 2007, then it probably would've happened then.