diff --git a/pvtoolsSrc/pvlist.cpp b/pvtoolsSrc/pvlist.cpp
index 573ebe3..ddc42ac 100644
--- a/pvtoolsSrc/pvlist.cpp
+++ b/pvtoolsSrc/pvlist.cpp
@@ -120,6 +120,10 @@ bool processSearchResponse(osiSockAddr const & responseFrom, ByteBuffer & receiv
 
     // second byte version
     int8 version = receiveBuffer.getByte();
+    if(version == 0) {
+        // 0 -> 1 included incompatible changes
+        return false;
+    }
 
     // only data for UDP
     int8 flags = receiveBuffer.getByte();
diff --git a/src/remote/blockingUDPTransport.cpp b/src/remote/blockingUDPTransport.cpp
index db0e366..77c0797 100644
--- a/src/remote/blockingUDPTransport.cpp
+++ b/src/remote/blockingUDPTransport.cpp
@@ -341,6 +341,10 @@ bool BlockingUDPTransport::processBuffer(Transport::shared_pointer const & trans
 
         // second byte version
         int8 version = receiveBuffer->getByte();
+        if(version==0) {
+            // 0 -> 1 included incompatible changes
+            return false;
+        }
 
         int8 flags = receiveBuffer->getByte();
         if (flags & 0x80)
diff --git a/src/remote/codec.cpp b/src/remote/codec.cpp
index 0ee4c11..e4ad3a4 100644
--- a/src/remote/codec.cpp
+++ b/src/remote/codec.cpp
@@ -159,12 +159,12 @@ void AbstractCodec::processHeader() {
     _payloadSize = _socketBuffer.getInt();
 
     // check magic code
-    if (magicCode != PVA_MAGIC)
+    if (magicCode != PVA_MAGIC || _version==0)
     {
         LOG(logLevelError,
-            "Invalid header received from the client at %s:%d: %s.,"
-            " disconnecting...",
-            __FILE__, __LINE__, inetAddressToString(*getLastReadBufferSocketAddress()).c_str());
+            "Invalid header received from the client : %s %02x%02x%02x%02x disconnecting...",
+            inetAddressToString(*getLastReadBufferSocketAddress()).c_str(),
+            unsigned(magicCode), unsigned(_version), unsigned(_flags), unsigned(_command));
         invalidDataStreamHandler();
         throw invalid_data_stream_exception("invalid header received");
     }