Backwards compatibility

nano/node/messages.cpp

@@ -1036,14 +1036,13 @@ bool nano::telemetry_ack::deserialize (nano::stream & stream_a)
 	{
 		if (!is_empty_payload ())
 		{
-			data.deserialize (stream_a, nano::narrow_cast<uint16_t> (header.extensions.to_ulong ()));
+			data.deserialize (stream_a, size ());
 		}
 	}
 	catch (std::runtime_error const &)
 	{
-		error = true;
+		// Ignore deserialization errors for backwards compatibility
 	}
-
 	return error;
 }
 
@@ -1084,6 +1083,7 @@ void nano::telemetry_ack::operator() (nano::object_stream & obs) const
 void nano::telemetry_data::deserialize (nano::stream & stream, uint16_t payload_length)
 {
 	read (stream, signature);
+
 	read (stream, node_id);
 	read (stream, block_count);
 	boost::endian::big_to_native_inplace (block_count);
@@ -1118,6 +1118,7 @@ void nano::telemetry_data::deserialize (nano::stream & stream, uint16_t payload_
 	read (stream, active_difficulty);
 	boost::endian::big_to_native_inplace (active_difficulty);
 
+	// Added in V27, will throw if not present
 	uint8_t database_backend_l;
 	read (stream, database_backend_l);
 	database_backend = static_cast<nano::telemetry_backend> (database_backend_l);