Fixed negative class number bug in span reference query.

Change-Id: I5f232e771c54a20aa13650823c5b78884b5d4a1b
diff --git a/Changes b/Changes
index 828386e..f2dd94e 100644
--- a/Changes
+++ b/Changes
@@ -1,9 +1,10 @@
-0.59.3 2021-02-18
+0.59.3 2021-06-28
     - [feature] Added "missing query reference" status code (diewald)
     - [cleanup] Added test coverage checking with
       $ mvn cobertura:cobertura (diewald, kupietz)
     - [cleanup] Added test statistics with referTo and pubDate (margaretha)
     - [cleanup] Fixed TestCollectionCache (margaretha)
+    - [cleanup] Fixed negative class number bug in span reference query (margaretha)
 
 0.59.2 2020-07-24
     - [feature] Add fingerprint method to index (diewald)