I need to install the full OSGeo4W64 version for 2.18.6, Windows 10, 64-bit. However, the previous release page only has the standalone QGIS installer:
http://download.osgeo.org/qgis/windows/QGIS-OSGeo4W-2.18.6-1-Setup-x86_64.exe
Where do I find the full OSGeoW64 installer for 2.18.6?
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Edit:
After following the answer from @mgri below, I get the following error when I try to run 2.18.6:
However, qgis_app.dll does exist, in the correct path.
I have reinstalled twice, each time using the latest full OSGeoW64 installer (which is the only installer I am aware of, and installs 2.18.7 by default). The first time I followed mgri's instructions at the initial install, requesting 2.18.6. The error ensued. The second time I installed 2.18.7, then went back and did a custom install, again following mgri's instructions, and modified the install to revert to 2.18.6. Again, the error.
After an internet search regarding "Entry Point Not Found", I ran the Windows System File Checker, but it turned up no problems.
I am still unable to install 2.18.6, looking for assistance.