Just find an unaltered version of
SDR# v1716 to use as a base install.
The Airspy site used to have it, but gone now.
There maybe a link on RR somewhere (or someone can post link again here)
Then use link below to download and then install the updated
Frequency Scanner plug-in.
NOTE: Don't go installing every plug-in under the sun. This will lead to disappointment, guaranteed.
Various updated SDR# plug-ins can be found here: MEGA - Download
These plug-ins have documentation for installation and usage, please read.