Maxwell Render | Official public forum

Can anyone direct me to where I can download the plug-in for SU 2015 for Maxwell Render Suite V2

There is no V2-series plugin for SketchUp 2015 x64, because Maxwell V3 was released around a year before SketchUp 2015.

So only resolution is to upgrade to Maxwell Render Suite v3?

In order to use SketchUp 2014 or newer, yes, as the most recent version supported in the V2 plugin was SketchUp 2013.

It would be completely unsupported, but if I recall correctly, it may be possible to install SketchUp 2013 (you can still get that on the SketchUp downloads page), install the SketchUp 2013 x86 version of the Maxwell V2 plugin (available through your account on the https://portal.nextlimit.com download page), and then manually transfer the plugin files over to a SketchUp 2015 x86 installation. But, as I say, this would be unsupported, and even if it works, would be limited to 32-bit, not 64, since there was of course no such thing as a 64-bit SketchUp until SU2015.