Update README.md

README.md

 [PACKAGE]: ../../raw/master/mkp/check_radius-0.1.0-20240428.mkp "check_radius-0.1.0-20240428.mkp"
-# Check RADIUS
+[PYRADLIB]: ../../raw/master/mkp/pyrad-2.4.0-240421.mkp "pyrad-2.4.0-240421.mkp"
 
 This is a (very) basic active RADIUS check. Tests if a RADIUS server is responsive (accept/reject/timeout). There is (limited) support to add AV-pairs to the RADIUS request.
 
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 ### Download
 * [Download latest mkp file][PACKAGE]
+* [pyrad-2.4.0-240421.mkp][PYRADLIB] The pyrad lib as MKP (contains pyrad 2.4, six 1.16.0, netaddr 1.2.1).
 
 **Note**: before you update to a newer version, always check the [CHANGELOG](CHANGELOG). There migth be incompatible changes.
                         
@@ -20,6 +21,8 @@ mkp enable PAKAGE_NAME VERSION
 
 In the Enterprise/Free/Cloud edition of CheckMK you can use the GUI to install the package (_Setup_ -> _Extension Packages_ -> _Upload package_)
 
+**Note**: before you can use this plugin you need to install the python lib [**_pyrad_**](https://github.com/pyradius/pyrad) into your CMK site. This can be done by issuing the command `pip3 install pyrad` as site user, as long as your CMK server has internet access. If you prefer not to download the pyrad lib from the internet you can also use the additional MKP package **_pyrad-2.4.0-240421.mkp_** (see above).
+
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 ### Want to Contribute?