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Hello everyone,
I just wanted to reach out regarding downgrading the domain and forest functional level. I found some instructions that looks like we would be able to downgrade functional levels from 2019 to 2008. I just wanted to confirm if this is indeed a possiblity, and I also want to ask what are the risks assiociated with this? Right now we only have one domain control that supports about 30 computers, and this looks like something we may need to do to get their XP machines to connect back to the domain again. Just looking to get some infomration regarding this process?
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Yes, you can do this but its unlikely to have any effect on joining XP members to the domain.
https://www.rebeladmin.com/2016/01/step-by-step-guide-to-downgrade-domain-and-forest-functional-level/
Windows security updates in the last 8 years are the reason.
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Just checking if there's any progress or updates?
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Thank you for checking in, so I have been pretty booked up today and haven't been able to go and assist them today. Just curious if we did drop down functionality wise can you go back up to the previous level if the lowered functionality doesnt work?
Shouldn't be a problem, just check that domain health and replication are 100% before making any changes either direction.
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Just checking if there's any progress or updates?
--please don't forget to upvote and Accept as answer if the reply is helpful--
Thanks for the response, so my customers don't want to go through with this because I can't guarentee it will work. I found an old microsoft article through the wayback machine and I am going to see if it works. Thanks for your help though!
Sounds good, you're welcome.
Hello
Thank you for your question and reaching out. I can understand you are having query\issues related to
When attempting to downgrade (lower) the DFL of a domain, you would first need to downgrade the FFL to the same level as the required DFL to be configured. The FFL can never be higher than the DFL of any domain in the forest.
Functional levels determine the available AD DS domain or forest capabilities.
In your case if you have XP Machines then you should be able to join to Windows 2019 DC , Hence there should be no need to downgrade functional level.
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Here is the wired thing is that they do have XP machines that are already connected to the domain and have been connected for awhile but the XP machines we are currently trying to connect now have been sitting on a shelf for who knows how long. I have ensureed that SMBv1 is enabled on the domain controller. I have tried applying an update that other blogs said might help, but this is the other thing I was able to find that might help.