diff --git a/server-application-server/source/java/ch/ethz/sis/openbis/generic/server/xls/importer/helper/DatasetTypeImportHelper.java b/server-application-server/source/java/ch/ethz/sis/openbis/generic/server/xls/importer/helper/DatasetTypeImportHelper.java
index d78bbecf13157fb261332e700046e164afb36253..846ef1dabc3545742c0c2513980a1c373dc8c94f 100644
--- a/server-application-server/source/java/ch/ethz/sis/openbis/generic/server/xls/importer/helper/DatasetTypeImportHelper.java
+++ b/server-application-server/source/java/ch/ethz/sis/openbis/generic/server/xls/importer/helper/DatasetTypeImportHelper.java
@@ -84,7 +84,7 @@ public class DatasetTypeImportHelper extends BasicImportHelper
         String version = getValueByColumnName(header, values, Attribute.Version);
         String code = getValueByColumnName(header, values, Attribute.Code);
 
-        if (version == null) {
+        if (version == null || version.isEmpty()) {
             return true;
         } else {
             return VersionUtils.isNewVersion(version, VersionUtils.getStoredVersion(versions, ImportTypes.DATASET_TYPE.getType(), code));
@@ -96,7 +96,7 @@ public class DatasetTypeImportHelper extends BasicImportHelper
         String version = getValueByColumnName(header, values, Attribute.Version);
         String code = getValueByColumnName(header, values, Attribute.Code);
 
-        if (version == null) {
+        if (version == null || version.isEmpty()) {
             Integer storedVersion = VersionUtils.getStoredVersion(versions, ImportTypes.DATASET_TYPE.getType(), code);
             storedVersion++;
             version = storedVersion.toString();
diff --git a/server-application-server/source/java/ch/ethz/sis/openbis/generic/server/xls/importer/helper/ExperimentTypeImportHelper.java b/server-application-server/source/java/ch/ethz/sis/openbis/generic/server/xls/importer/helper/ExperimentTypeImportHelper.java
index df1eb2cfc55c8169c484d9925a3363be890bc1ae..08c927014dbcb5e6f835654c00fc774b87817c4f 100644
--- a/server-application-server/source/java/ch/ethz/sis/openbis/generic/server/xls/importer/helper/ExperimentTypeImportHelper.java
+++ b/server-application-server/source/java/ch/ethz/sis/openbis/generic/server/xls/importer/helper/ExperimentTypeImportHelper.java
@@ -84,7 +84,7 @@ public class ExperimentTypeImportHelper extends BasicImportHelper
         String version = getValueByColumnName(header, values, Attribute.Version);
         String code = getValueByColumnName(header, values, Attribute.Code);
 
-        if (version == null) {
+        if (version == null || version.isEmpty()) {
             return true;
         } else {
             return VersionUtils.isNewVersion(version, VersionUtils.getStoredVersion(versions, ImportTypes.EXPERIMENT_TYPE.getType(), code));
@@ -96,7 +96,7 @@ public class ExperimentTypeImportHelper extends BasicImportHelper
         String version = getValueByColumnName(header, values, Attribute.Version);
         String code = getValueByColumnName(header, values, Attribute.Code);
 
-        if (version == null) {
+        if (version == null || version.isEmpty()) {
             Integer storedVersion = VersionUtils.getStoredVersion(versions, ImportTypes.EXPERIMENT_TYPE.getType(), code);
             storedVersion++;
             version = storedVersion.toString();
diff --git a/server-application-server/source/java/ch/ethz/sis/openbis/generic/server/xls/importer/helper/PropertyAssignmentImportHelper.java b/server-application-server/source/java/ch/ethz/sis/openbis/generic/server/xls/importer/helper/PropertyAssignmentImportHelper.java
index 90edfeb46e33698816fc33196d0c758e568c49ec..e8ae70bdd738ad47abe17f7c0bca8070129b1b76 100644
--- a/server-application-server/source/java/ch/ethz/sis/openbis/generic/server/xls/importer/helper/PropertyAssignmentImportHelper.java
+++ b/server-application-server/source/java/ch/ethz/sis/openbis/generic/server/xls/importer/helper/PropertyAssignmentImportHelper.java
@@ -122,7 +122,7 @@ public class PropertyAssignmentImportHelper extends BasicImportHelper
         String version = getValueByColumnName(header, values, PropertyAssignmentImportHelper.Attribute.Version);
         String code = getValueByColumnName(header, values, PropertyAssignmentImportHelper.Attribute.Code);
 
-        if (version == null) {
+        if (version == null || version.isEmpty()) {
             return true;
         } else {
             return !existingCodes.contains(code) || VersionUtils.isNewVersion(version, VersionUtils.getStoredVersion(beforeVersions, ImportTypes.PROPERTY_TYPE.getType(), code));
diff --git a/server-application-server/source/java/ch/ethz/sis/openbis/generic/server/xls/importer/helper/PropertyTypeImportHelper.java b/server-application-server/source/java/ch/ethz/sis/openbis/generic/server/xls/importer/helper/PropertyTypeImportHelper.java
index f285c33cfe2b6cfeeffca1a3acca2a185c7435b5..d521d9d87b1940426d0c6d68b1a9c9a0e5b5c3c7 100644
--- a/server-application-server/source/java/ch/ethz/sis/openbis/generic/server/xls/importer/helper/PropertyTypeImportHelper.java
+++ b/server-application-server/source/java/ch/ethz/sis/openbis/generic/server/xls/importer/helper/PropertyTypeImportHelper.java
@@ -145,7 +145,7 @@ public class PropertyTypeImportHelper extends BasicImportHelper
         String version = getValueByColumnName(header, values, Attribute.Version);
         String code = getValueByColumnName(header, values, Attribute.Code);
 
-        if (version == null) {
+        if (version == null || version.isEmpty()) {
             return true;
         } else {
             return VersionUtils.isNewVersion(version,
@@ -159,7 +159,7 @@ public class PropertyTypeImportHelper extends BasicImportHelper
         String version = getValueByColumnName(header, values, Attribute.Version);
         String code = getValueByColumnName(header, values, Attribute.Code);
 
-        if (version == null) {
+        if (version == null || version.isEmpty()) {
             Integer storedVersion = VersionUtils.getStoredVersion(versions, ImportTypes.PROPERTY_TYPE.getType(), code);
             storedVersion++;
             version = storedVersion.toString();
diff --git a/server-application-server/source/java/ch/ethz/sis/openbis/generic/server/xls/importer/helper/SampleTypeImportHelper.java b/server-application-server/source/java/ch/ethz/sis/openbis/generic/server/xls/importer/helper/SampleTypeImportHelper.java
index cef78f1424fba54a54efb955f5abeaade93c73d2..1be39ab4e5cde9b58a6989998d0b23610fcf79f2 100644
--- a/server-application-server/source/java/ch/ethz/sis/openbis/generic/server/xls/importer/helper/SampleTypeImportHelper.java
+++ b/server-application-server/source/java/ch/ethz/sis/openbis/generic/server/xls/importer/helper/SampleTypeImportHelper.java
@@ -86,7 +86,7 @@ public class SampleTypeImportHelper extends BasicImportHelper
         String version = getValueByColumnName(header, values, Attribute.Version);
         String code = getValueByColumnName(header, values, Attribute.Code);
 
-        if (version == null) {
+        if (version == null || version.isEmpty()) {
             return true;
         } else {
             return VersionUtils.isNewVersion(version, VersionUtils.getStoredVersion(versions, ImportTypes.SAMPLE_TYPE.getType(), code));
@@ -98,7 +98,7 @@ public class SampleTypeImportHelper extends BasicImportHelper
         String version = getValueByColumnName(header, values, Attribute.Version);
         String code = getValueByColumnName(header, values, Attribute.Code);
 
-        if (version == null) {
+        if (version == null || version.isEmpty()) {
             Integer storedVersion = VersionUtils.getStoredVersion(versions, ImportTypes.SAMPLE_TYPE.getType(), code);
             storedVersion++;
             version = storedVersion.toString();