I have the feeling Docker only works for Windows 10:
Important Notes:
Docker for Windows requires 64bit Windows 10 Pro, Enterprise and Education (1511 November update, Build 10586 or later) and Microsoft Hyper-V. Please see What to know before you install for a full list of prerequisites.
Does it work for Windows 8.1 x64 pro ? This is confusing. (I saw topic on the forum about W8 x64, so I assume it does work)
what are the differences between the “normal” docker and the toolbox, or are there any?
also wouldnt it make sense to put an info on the docker for windows download page when you surf on it with win7 or 8?