diff --git a/waveform-generator/src/main/java/uk/ac/ucl/rits/inform/datasources/waveform_generator/Hl7Generator.java b/waveform-generator/src/main/java/uk/ac/ucl/rits/inform/datasources/waveform_generator/Hl7Generator.java
index 48bb18bb3..c9c04eed8 100644
--- a/waveform-generator/src/main/java/uk/ac/ucl/rits/inform/datasources/waveform_generator/Hl7Generator.java
+++ b/waveform-generator/src/main/java/uk/ac/ucl/rits/inform/datasources/waveform_generator/Hl7Generator.java
@@ -116,8 +116,7 @@ private String applyHl7Template(long samplingRate, String locationId, Instant ob
                 OBX|${obxI}|${dataType}|${streamId}||${valuesAsStr}||||||F||20|${obsTimeStr}|\r\
                 """;
         ZoneId hospitalTimezone = ZoneId.of("Europe/London");
-        // XXX: shouldn't this be yyyy?
-        DateTimeFormatter formatter = DateTimeFormatter.ofPattern("YYYYMMddHHmmss.SSSZZ");
+        DateTimeFormatter formatter = DateTimeFormatter.ofPattern("yyyyMMddHHmmss.SSSZZ");
         // XXX: where to get message timestamp from? Just add a random bit maybe?
         // Will sampling rate have to be inferred at the other end? It's in the coding table I think...
         // message Id I think shouldn't be created here