diff --git a/Server-Protocol-Buffer/src/main/proto/internal/pt/trace_warning.proto b/Server-Protocol-Buffer/src/main/proto/internal/pt/trace_warning.proto
index 3696b4ac92e4c1e76b6b532263a8adbc0c58ed5a..e6df1c6bdb5476552e7017aabea2a3e5896363c5 100644
--- a/Server-Protocol-Buffer/src/main/proto/internal/pt/trace_warning.proto
+++ b/Server-Protocol-Buffer/src/main/proto/internal/pt/trace_warning.proto
@@ -13,7 +13,7 @@ message TraceWarningPackage {
 }
 
 message TraceTimeIntervalWarning {
-  string locationGuid = 1; // uuid
+  bytes locationGuidHash = 1; // Hash of the Location GUID
   // 10-minute intervals since UNIX Epoch
   uint32 startIntervalNumber = 2;
   // Number of 10-minute intervals to which the warning applies