Hi Dave,
I downloaded the Zibo 737-700U and the FMC showed NAV DATA OUT OF DATE. The X-Plane 11.50(11.50+) dataset used by the Zibo Mod , had been updated to AIRAC 2107.
There was an issue with the Zibo 737-800X, where the FMC showed NAV DATA OUT OF DATE, even though it had been updated. Please see FMS data not working for ZIBO mod 737 - #4 by Tony31841. An updated version was issued by Zibo to fix it.
Maybe the Zibo 737-700U needs a similar updated version. I suggest you speak with the Zibo 737-700U maintainers.
See also Navigraph didn't update the Zibo 738? - ZIBO B738-800 modified - X-Plane.Org Forum
Cheers
Ian