diff --git a/build.gradle b/build.gradle
index a6abfb7..3cb1c8c 100644
--- a/build.gradle
+++ b/build.gradle
@@ -14,7 +14,7 @@
 
 description = 'MDM API - ODSAdapter'
 group = 'org.eclipse.mdm'
-version = '5.1.0M3'
+version = '5.1.0M6-SNAPSHOT'
 
 apply plugin: 'java'
 apply plugin: 'maven'
diff --git a/src/main/java/org/eclipse/mdm/api/odsadapter/ReadRequestHandler.java b/src/main/java/org/eclipse/mdm/api/odsadapter/ReadRequestHandler.java
index 69c87f4..8a1aac1 100644
--- a/src/main/java/org/eclipse/mdm/api/odsadapter/ReadRequestHandler.java
+++ b/src/main/java/org/eclipse/mdm/api/odsadapter/ReadRequestHandler.java
@@ -258,7 +258,7 @@
 
 				Set<String> setColumnNames = mapColumns.keySet();
 
-				Map<Long, ColumnAttributes> mapColumnAttributes = new HashMap<>();
+				Map<String, ColumnAttributes> mapColumnAttributes = new HashMap<>();
 
 				for (Result result : query1.fetch(filter)) {
 					Map<String, Value> mapValues = result.getRecord(localColumnEntityType).getValues();
@@ -291,7 +291,7 @@
 					}
 				}
 
-				for (Map.Entry<Long, ColumnAttributes> me : mapColumnAttributes.entrySet()) {
+				for (Map.Entry<String, ColumnAttributes> me : mapColumnAttributes.entrySet()) {
 					ColumnAttributes ca = me.getValue();
 					listColumnPairs.add(new ImmutablePair<Column, ColumnAttributes>(mapColumns.get(ca.getName()), ca));
 				}