Offline Maps data on Windows 10 Mobile has received an update. You may get a notification in the action center about the update availability. Else if you now go and check you will be informed about availability of the maps update.
For checking the update availability, one need to got to Settings–>System–>Offline Maps–>Check now. In case you have enabled “Automatically update Maps”, chances are, it is already updated in background.
Coming to what changes this updated Maps data brings, there is no official word but HERE may post about Maps data update. Since Windows Maps still uses HERE Maps data it should be valid for Windows 10 Mobile too.
We will update this article with changelog, when available.