docs: updated info about BIND/nsupdate on Windows

docs/Plugins/RFC2136.md

@@ -21,7 +21,9 @@ When using a TSIG key, you will typically have 3 values; a key name, a key type
 
 ### Plugin Dependencies
 
-Due to the inexplicable lack of good native DNS libraries within PowerShell/.NET, this plugin relies on the `nsupdate` utility which is part of the ISC BIND distribution. Most modern Linux distributions will have this installed by default, but double check to be sure. **On Windows, you will need to download and install the utility.** Go to the [ISC BIND Downloads](https://www.isc.org/download/) page and download the current stable version for Windows. You don't actually need to run the installer. It is sufficient to simply unzip the archive and either add that folder to your `PATH` environment variable or specify the full path to `nsupdate.exe` in the plugin arguments. *(Adding the folder to your PATH also gives you easy access to the `dig` utility which many DNS admins prefer over nslookup)*
+Due to the inexplicable lack of good native DNS libraries within PowerShell/.NET, this plugin relies on the `nsupdate` utility which is part of the ISC BIND distribution. Most modern Linux distributions will have this installed by default, but double check to be sure. **On Windows, you will need to download and install the utility.** However, ISC has discontinued support for BIND (and its utilities) Windows since version 9.18. The last official build was 9.17.15 and is still available from their website here, [https://downloads.isc.org/isc/bind9/9.17.15/BIND9.17.15.x64.zip](https://downloads.isc.org/isc/bind9/9.17.15/BIND9.17.15.x64.zip). It may also be possible to use the Linux version from Windows via [WSL (Windows Subsystem for Linux)](https://learn.microsoft.com/en-us/windows/wsl/install).
+
+For the Windows version, you don't technically need to run the BIND installer. It is usually sufficient to simply unzip the archive and either add the folder to your `PATH` environment variable or specify the full path to `nsupdate.exe` in the plugin arguments. *(Adding the folder to your PATH also gives you easy access to the `dig` utility which many DNS admins prefer over nslookup)*
 
 !!! note
     Some users have reported needing to install Visual C++ Redistributable libraries in order for the unzip-and-run method to work. Many systems will already have these installed. But if not, among the files unzipped should be a `vcredist_x64.exe` installer you can use. You can test by running `nsupdate -V` to check the version.