The website always contains the latest (in this case, 100.7) as well as the prior generation (10.2.6). The information available for 100.7 should be applicable for 100.4 as well. The only difference is there have been API additions. However, our documentation uses the "Since 100.5" tags, so it should be easy to deciminate what is available with 100.4 vs newer builds.
I will also note that the SDK installs also contains the QCH files for the API ref (but not guide doc). If you run the post installer, the help will be added to Qt Creator.