diff --git a/src/SIPSorcery/net/STUN/STUNAppState.cs b/src/SIPSorcery/net/STUN/STUNAppState.cs
index 715ec84bf..7b20c1714 100644
--- a/src/SIPSorcery/net/STUN/STUNAppState.cs
+++ b/src/SIPSorcery/net/STUN/STUNAppState.cs
@@ -40,7 +40,7 @@ public static string PrintBuffer(byte[] buffer)
 
                 if (byteStr.Length == 1)
                 {
-                    bufferStr += "0" + byteStr;
+                    bufferStr += $"0{byteStr}";
                 }
                 else
                 {
diff --git a/src/SIPSorcery/net/STUN/STUNAttributes/STUNAddressAttribute.cs b/src/SIPSorcery/net/STUN/STUNAttributes/STUNAddressAttribute.cs
index 620b267df..0fb559f68 100644
--- a/src/SIPSorcery/net/STUN/STUNAttributes/STUNAddressAttribute.cs
+++ b/src/SIPSorcery/net/STUN/STUNAttributes/STUNAddressAttribute.cs
@@ -95,7 +95,7 @@ public override int ToByteBuffer(byte[] buffer, int startIndex)
 
         public override string ToString()
         {
-            string attrDescrStr = "STUN Attribute: " + base.AttributeType + ", address=" + Address.ToString() + ", port=" + Port + ".";
+            string attrDescrStr = $"STUN Attribute: {base.AttributeType}, address={Address.ToString()}, port={Port}.";
 
             return attrDescrStr;
         }
diff --git a/src/SIPSorcery/net/STUN/STUNAttributes/STUNAttribute.cs b/src/SIPSorcery/net/STUN/STUNAttributes/STUNAttribute.cs
index 8df861b5b..74dd29cca 100644
--- a/src/SIPSorcery/net/STUN/STUNAttributes/STUNAttribute.cs
+++ b/src/SIPSorcery/net/STUN/STUNAttributes/STUNAttribute.cs
@@ -220,7 +220,7 @@ public static List<STUNAttribute> ParseMessageAttributes(byte[] buffer, int star
 
                     attributes.Add(attribute);
 
-                    // Attributes start on 32 bit word boundaries so where an attribute length is not a multiple of 4 it gets padded. 
+                    // Attributes start on 32 bit word boundaries so where an attribute length is not a multiple of 4 it gets padded.
                     int padding = (stunAttributeLength % 4 != 0) ? 4 - (stunAttributeLength % 4) : 0;
 
                     startAttIndex = startAttIndex + 4 + stunAttributeLength + padding;
@@ -258,7 +258,7 @@ public virtual int ToByteBuffer(byte[] buffer, int startIndex)
 
         public new virtual string ToString()
         {
-            string attrDescrString = "STUN Attribute: " + AttributeType.ToString() + ", length=" + PaddedLength + ".";
+            string attrDescrString = $"STUN Attribute: {AttributeType.ToString()}, length={PaddedLength}.";
 
             return attrDescrString;
         }
diff --git a/src/SIPSorcery/net/STUN/STUNAttributes/STUNChangeRequestAttribute.cs b/src/SIPSorcery/net/STUN/STUNAttributes/STUNChangeRequestAttribute.cs
index 94608dfad..b41738deb 100644
--- a/src/SIPSorcery/net/STUN/STUNAttributes/STUNChangeRequestAttribute.cs
+++ b/src/SIPSorcery/net/STUN/STUNAttributes/STUNChangeRequestAttribute.cs
@@ -53,7 +53,7 @@ public STUNChangeRequestAttribute(byte[] attributeValue)
 
         public override string ToString()
         {
-            string attrDescrStr = "STUN Attribute: " + STUNAttributeTypesEnum.ChangeRequest.ToString() + ", key byte=" + m_changeRequestByte.ToString("X") + ", change address=" + ChangeAddress + ", change port=" + ChangePort + ".";
+            string attrDescrStr = $"STUN Attribute: {STUNAttributeTypesEnum.ChangeRequest.ToString()}, key byte={m_changeRequestByte.ToString("X")}, change address={ChangeAddress}, change port={ChangePort}.";
 
             return attrDescrStr;
         }
diff --git a/src/SIPSorcery/net/STUN/STUNAttributes/STUNConnectionIdAttribute.cs b/src/SIPSorcery/net/STUN/STUNAttributes/STUNConnectionIdAttribute.cs
index 78244fd7e..bce3d091c 100644
--- a/src/SIPSorcery/net/STUN/STUNAttributes/STUNConnectionIdAttribute.cs
+++ b/src/SIPSorcery/net/STUN/STUNAttributes/STUNConnectionIdAttribute.cs
@@ -44,7 +44,7 @@ public STUNConnectionIdAttribute(uint connectionId)
 
         public override string ToString()
         {
-            string attrDescrStr = "STUN CONNECTION_ID Attribute: value=" + ConnectionId + ".";
+            string attrDescrStr = $"STUN CONNECTION_ID Attribute: value={ConnectionId}.";
 
             return attrDescrStr;
         }
diff --git a/src/SIPSorcery/net/STUN/STUNAttributes/STUNErrorCodeAttribute.cs b/src/SIPSorcery/net/STUN/STUNAttributes/STUNErrorCodeAttribute.cs
index 097486d2d..709af72a1 100644
--- a/src/SIPSorcery/net/STUN/STUNAttributes/STUNErrorCodeAttribute.cs
+++ b/src/SIPSorcery/net/STUN/STUNAttributes/STUNErrorCodeAttribute.cs
@@ -60,7 +60,7 @@ private static byte[] BuildValue(int errorCode, string reasonPhrase)
 
         public override string ToString()
         {
-            string attrDescrStr = "STUN ERROR_CODE_ADDRESS Attribute: error code=" + ErrorCode + ", reason phrase=" + ReasonPhrase + ".";
+            string attrDescrStr = $"STUN ERROR_CODE_ADDRESS Attribute: error code={ErrorCode}, reason phrase={ReasonPhrase}.";
 
             return attrDescrStr;
         }
diff --git a/src/SIPSorcery/net/STUN/STUNAttributes/STUNXORAddressAttribute.cs b/src/SIPSorcery/net/STUN/STUNAttributes/STUNXORAddressAttribute.cs
index e76a7b1e9..544256c42 100644
--- a/src/SIPSorcery/net/STUN/STUNAttributes/STUNXORAddressAttribute.cs
+++ b/src/SIPSorcery/net/STUN/STUNAttributes/STUNXORAddressAttribute.cs
@@ -133,7 +133,7 @@ public override int ToByteBuffer(byte[] buffer, int startIndex)
 
         public override string ToString()
         {
-            string attrDescrStr = "STUN XOR_MAPPED_ADDRESS Attribute: " + base.AttributeType + ", address=" + Address.ToString() + ", port=" + Port + ".";
+            string attrDescrStr = $"STUN XOR_MAPPED_ADDRESS Attribute: {base.AttributeType}, address={Address.ToString()}, port={Port}.";
 
             return attrDescrStr;
         }
diff --git a/src/SIPSorcery/net/STUN/STUNMessage.cs b/src/SIPSorcery/net/STUN/STUNMessage.cs
index 2bdcdd541..ebde01549 100644
--- a/src/SIPSorcery/net/STUN/STUNMessage.cs
+++ b/src/SIPSorcery/net/STUN/STUNMessage.cs
@@ -198,13 +198,13 @@ public byte[] ToByteBuffer(byte[] messageIntegrityKey, bool addFingerprint)
             return buffer;
         }
 
-        public new string ToString()
+        public override string ToString()
         {
-            string messageDescr = "STUN Message: " + Header.MessageType.ToString() + ", length=" + Header.MessageLength;
+            string messageDescr = $"STUN Message: {Header.MessageType.ToString()}, length={Header.MessageLength}";
 
             foreach (STUNAttribute attribute in Attributes)
             {
-                messageDescr += "\n " + attribute.ToString();
+                messageDescr += $"\n {attribute.ToString()}";
             }
 
             return messageDescr;