Microsoft follows a clear versioning scheme for Windows 10: YYMM (Year-Month). For example:
While direct downloads are rare, sometimes old builds are available through the Volume Licensing Service Center (VLSC) or Visual Studio Subscriptions for subscribers. windows 10 1603 iso download repack
The uploader likely meant 1607 (the actual 2016 update) or 1703. Microsoft follows a clear versioning scheme for Windows