I'm trying to avoid updating the 2012 R2 schema (2008 R2 functional level) by adding a custom attribute like "otherAddresses".
I can't use the Exchange Custom Attributes because disabling a mailbox of a user would wipe those out of an active user.
My fear of adding a custom attribute is no test environment to do it in, no rollback plan/experience of recovering a Forest, and that adding a new attribute means all the DC's will re-sync every attribute in the Forest, causing network load and CPU issues.
So I'm considering what attributes exist that can store a personal e-mail address (like a gmail or yahoo address), as well as having the ability to store other information like a mailing address (123 Abc St, City, ST zip).
I came across the "unstructuredAddress" attribute. I'm not sure what this is for or what class it's typically associated with. Googling says it's for a router IP? Is that just an example? Could it be used for what I'm looking to store in there?
Any other suggestions for typically uncommon attributes for user/person class in AD that can be utilized for my need?