diff --git a/src/IPAddressExtensions.cs b/src/IPAddressExtensions.cs
deleted file mode 100644
index d9a6099..0000000
--- a/src/IPAddressExtensions.cs
+++ /dev/null
@@ -1,49 +0,0 @@
-using System;
-using System.Linq;
-using System.Net;
-using System.Net.Sockets;
-using System.Text;
-
-namespace Makaretu.Dns
-{
-    /// <summary>
-    ///   Extension methods for <see cref="IPAddress"/>.
-    /// </summary>
-    /// <remarks>
-    ///   Original code copied from <see href="https://github.com/MichaCo/DnsClient.NET/blob/dev/src/DnsClient/IpAddressExtensions.cs"/> 
-    /// </remarks>
-    public static class IPAddressExtensions
-    {
-        /// <summary>
-        /// Translates a IPv4 or IPv6 address into an arpa address.
-        /// Used for reverse DNS lookup to get the domain name of the given address.
-        /// </summary>
-        /// <param name="ip">The address to translate.</param>
-        /// <returns>The arpa representation of the address.</returns>
-        /// <seealso href="https://en.wikipedia.org/wiki/.arpa"/>
-        public static string GetArpaName(this IPAddress ip)
-        {
-            var bytes = ip.GetAddressBytes();
-            Array.Reverse(bytes);
-
-            // check IP6
-            if (ip.AddressFamily == AddressFamily.InterNetworkV6)
-            {
-                // reveresed bytes need to be split into 4 bit parts and separated by '.'
-                var newBytes = bytes
-                    .SelectMany(b => new[] { (b >> 0) & 0xf, (b >> 4) & 0xf })
-                    .Aggregate(new StringBuilder(), (s, b) => s.Append(b.ToString("x")).Append(".")) + "ip6.arpa";
-
-                return newBytes;
-            }
-            else if (ip.AddressFamily == AddressFamily.InterNetwork)
-            {
-                // else IP4
-                return string.Join(".", bytes) + ".in-addr.arpa";
-            }
-
-            // never happens anyways!?
-            throw new ArgumentException($"Unsupported address family '{ip.AddressFamily}'.", nameof(ip));
-        }
-    }
-}
\ No newline at end of file
diff --git a/src/Udns.csproj b/src/Udns.csproj
index c653996..0fbf028 100644
--- a/src/Udns.csproj
+++ b/src/Udns.csproj
@@ -31,7 +31,7 @@
 
   <ItemGroup>
     <PackageReference Include="Common.Logging" Version="3.4.1" />
-    <PackageReference Include="Makaretu.Dns" Version="1.4.1" />
+    <PackageReference Include="Makaretu.Dns" Version="1.5.0" />
     <PackageReference Include="Nito.AsyncEx" Version="5.0.0" />
   </ItemGroup>
   
diff --git a/test/IPAddressExtensionsTest.cs b/test/IPAddressExtensionsTest.cs
deleted file mode 100644
index e244cc0..0000000
--- a/test/IPAddressExtensionsTest.cs
+++ /dev/null
@@ -1,27 +0,0 @@
-using Makaretu.Dns;
-using Microsoft.VisualStudio.TestTools.UnitTesting;
-using System;
-using System.Collections.Generic;
-using System.IO;
-using System.Linq;
-using System.Net;
-using System.Net.NetworkInformation;
-using System.Net.Sockets;
-using System.Threading;
-using System.Threading.Tasks;
-
-namespace Makaretu.Dns
-{
-    
-    [TestClass]
-    public class IPAddressExtensionsTest
-    {
-        [TestMethod]
-        public void ArpaName()
-        {
-            Assert.AreEqual("4.4.8.8.in-addr.arpa", IPAddress.Parse("8.8.4.4").GetArpaName());
-            Assert.AreEqual("b.a.9.8.7.6.5.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.8.b.d.0.1.0.0.2.ip6.arpa", IPAddress.Parse("2001:db8::567:89ab").GetArpaName());
-        }
-
-    }
-}