diff --git a/slsReceiverSoftware/include/ZmqSocket.h b/slsReceiverSoftware/include/ZmqSocket.h
index e58419a1e..5b569f94a 100644
--- a/slsReceiverSoftware/include/ZmqSocket.h
+++ b/slsReceiverSoftware/include/ZmqSocket.h
@@ -286,7 +286,7 @@ public:
 		        "\"flippedDataX\":%u"
 
 				;//"}\n";
-		int length = sprintf(buf, jsonHeaderFormat,
+		sprintf(buf, jsonHeaderFormat,
 				jsonversion, dynamicrange, fileIndex, npixelsx, npixelsy, imageSize,
 				acqIndex, fIndex, (fname == NULL)? "":fname, dummy?0:1,
 
@@ -298,10 +298,12 @@ public:
 						((flippedData == 0 ) ? 0 :flippedData[0])
 		);
 		if (additionalJsonHeader && strlen(additionalJsonHeader)) {
-		    length = sprintf(buf, "%s, %s}\n", buf, additionalJsonHeader);
-		} else {
-		    length = sprintf(buf, "%s}\n", buf);
+		    strcat(buf, ", ");
+		    strcat(buf, additionalJsonHeader);
 		}
+		strcat(buf,"}\n");
+		int length = strlen(buf);
+		
 
 #ifdef VERBOSE
 		//if(!index)