<div>
There's really no risk. The functional levels dictate the earliest version of Windows Server that can run on a domain controller, but they don't have any effect on the versions you can run on member servers or clients. If all of your DCs are running 2012 R2 and you don't plan on adding a DC running an earlier version, go ahead and raise the domain and forest functional levels to 2012 R2.
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IT Professional

Albert Widjaja

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hello DrDave242,<br />
<br />
there is no changing in security authentification ? that domain controller can use and xp and 2003 server cannot?
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<div>
XP might face issues while accessing smb shares in pure 2012 R2 DC Environment as it runs smb v1 and 2012 R2 runs on smb 3.0<br />
If I recollect correctly, smb1 is enabled by default on 2012 R2 but still u may face problems<br />
<br />
Apart from that i did not aware about any issues
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<div>
Further if you have dot net 3. 5 sp1 and less version apps, you might need patch if face issues<br />
<a href="https://blogs.technet.microsoft.com/askds/2011/06/14/what-is-the-impact-of-upgrading-the-domain-or-forest-functional-level/" rel="ugc">https://blogs.technet.microsoft.com/askds/2011/06/14/what-is-the-impact-of-upgrading-the-domain-or-forest-functional-level/</a><br />
<br />
Article not directly applies to 2012 functional levels but point is valid in case of apps using dot net
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cawasaki

<div>
<blockquote>
my question for you Experts, any advice if i can go to windows 2012 functionnel level without risk?
</blockquote>
Windows XP and 2003 will happily function as members within a 2012 R2 domain
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<div>
The domain functional level and forest functional level only affect the versions of Windows you can have as your DCs. &nbsp;Once you raise the level, you can't have older DCs. <br />
<br />
XP and 2003 *COULD* stop working on the domain at any time. &nbsp;They are old. &nbsp;They are insecure. &nbsp;They are not updated anymore. &nbsp;Microsoft VERY likely isn't testing patches and updates being issued for much newer, supported operating systems. &nbsp;Microsoft COULD release a patch that effectively breaks connectivity for those XP/2003 systems and COULD simply choose not to do anything about it because those systems are 15 years old and people need to move on if technology is going to continue advancing they can't spend time on technology that's very outdated. &nbsp;<br />
<br />
You need to be moving off those systems as soon as possible or one day you could be in serious trouble.
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<div>
<div class="content wysiwyg-content">
hello<br />
<br />
i have migrate all our domain controller from w2008r2 to Windows 2012 r2 6 month ago.<br />
<br />
i am still on windows 2008 r2 functionnel level.<br />
<br />
we have some windows XP client and some windows 2003 application server.<br />
<br />
my question for you Experts, any advice if i can go to windows 2012 functionnel level without risk?<br />
<br />
thanks for help
</div>
</div>


hello

i have migrate all our domain controller from w2008r2 to Windows 2012 r2 6 month ago.

i am still on windows 2008 r2 functionnel level.

we have some windows XP client and some windows 2003 application server.

my question for you Experts, any advice if i can go to windows 2012 functionnel level without risk?

thanks for help

raise domain functionnel level from 2k8R2 to 2k12R2 ==&gt; what are the Risk

This topic area includes legacy versions of Windows prior to Windows 2000: Windows 3/3.1, Windows 95 and Windows 98, plus any other Windows-related versions including Windows Mobile.

Windows OS

Active Directory (AD) is a Microsoft brand for identity-related capabilities. In the on-premises world, Windows Server AD provides a set of identity capabilities and services, and is hugely popular (88% of Fortune 1000 and 95% of enterprises use AD). This topic includes all things Active Directory including DNS, Group Policy, DFS, troubleshooting, ADFS, and all other topics under the Microsoft AD and identity umbrella.

raise domain functionnel level from 2k8R2 to 2k12R2 ==&gt; what are the Risk

raise domain functionnel level from 2k8R2 to 2k12R2 ==> what are the Risk