One thing to note is that 11 is partly a renumbering. We do include signed but unofficial Interstates (695 over the Key Collapse, 895 south of 695, 80 west of 101), so we would still need to keep 515 until we determine enough signs have changed that it's gone.
And this is why I haven't yet pushed the update. "Does 515 still exist?" is a real question. How many cases of something like this have we had in the history of TM? I'm fine holding off on pulling the trigger because we're not adding any mileage, just changing a number and extending an overlay. I could also do the intermediate step of extending 11 but keeping 515 because 11 now has multiple tangible signs of extending beyond AASHTO approvals and 1 interchange.
On the NDOT side, nearly everything internal has made the switch, though there are still public-facing items that refer to I-515. Signs, from what I can tell on the forum, are nearing 50-50.