Which model (X150q or X150e) do you have?
Are you in the insider program or are you using a production build?
The current production build is version (10.0.10586).318 and was released about a month ago. If you are running the production build you would not have seen an update for a while, though It is possible that another cumulative update will appear next week.
I believe there was bug that stopped many insiders from updating to the latest preview version, but apparently that problem has been fixed.