I changed from 4 to 5 a while back and looked into doing it ourself. Their was a lot more involved than I ever considered. We ended up using our BP to do it and it ended up going over very clean.
Unless someone like ProjectManager09 has Provision to be able to help you do it, i would not even consider it. If you are moving from 5 to 7 digits, i expect we are talking about moving a lot of extensions. Making a patch using provision and loading it and being done worked really well.
Also think about every coverage path, station, VDN ,vector, hunt group, Voice messaging system, the list goes on and on..
Just my 2 cents worth after being there...
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