Whilst genral consumers have had Windows 10 version 1511 released in November for a while now those PCs using the current branch for buisness will have stayed on version 1507. The current branch for buisness is designed for enterprise envirements that would that like to defer feature updates so they can test stability etc before they roll them out to everyone.

Microsoft posted in a blog post:

 

If you have devices running Windows 10 1507, you need to understand the impact of the CBB declaration:

  • For devices being serviced using Windows Update for Business and configured to “Defer upgrades,” Windows 10 1511 will begin to deploy as soon as the updated media has been published. (Note that the deferral policies that specify an additional number of months to defer the feature update are not supported for devices running Windows 10 1507.)
  • For devices being serviced using Windows Server Updates Services, the updates to the existing Windows 10 1511 feature updates will need to be re-approved once the new updated media is received (unless you have an automatic update rule configured for the “Upgrades” category).
  • For those using the System Center Configuration Manager Windows 10 servicing plans to keep Windows 10 devices up to date, the updated media will be detected as “business ready,” causing servicing plans based on that “business ready” designation to begin to be evaluated.
  • For devices that will be upgraded using System Center Configuration Manager or Microsoft Deployment Toolkit task sequences, you may want to switch to the latest media (downloaded from the Volume Licensing Service Center) instead of the current Windows 10 1511 media. Alternatively, you can inject the March cumulative update (KB3140768) into your existing media.

 

This means that your work PC won’t necessarly get version 1511 straight away depending on how your IT adminstrators manage updates.