Windows 10 Get Windows 10 PRO 1607 build

[winadmin]

Hi!

I need 1607 build of win 10 pro because I have a special software that does not work with newer versions. Torrents and pirating is not an option as it will operate in a corporate environment, so it has to be a clean copy. Microsoft offers the latest. Do you have any idea how to get the mentioned build or at least an earlier one?
I was thinking of buying a licence with installation DVD, but resellers say it is not possible to check build number without opening the pack.

Thanks.

 

[kemical]

Support for the Anniversary build ended April 10th 2018 so it's going to be very difficult to find a kosher copy.

I did however, just for the hell of it, google for the 1607 iso and blow me this link appeared:
Windows 10 Anniversary Update ISO Download [ver. 1607] build 14393 - Softlay

You could always try it in a virtual machine?