diff --git a/src/test/java/net/hostsharing/hsadminng/hs/migration/CsvDataImport.java b/src/test/java/net/hostsharing/hsadminng/hs/migration/CsvDataImport.java
index 407e2673..084be3ca 100644
--- a/src/test/java/net/hostsharing/hsadminng/hs/migration/CsvDataImport.java
+++ b/src/test/java/net/hostsharing/hsadminng/hs/migration/CsvDataImport.java
@@ -253,7 +253,7 @@ class Record {
 
     Integer getInteger(final String columnName) {
         final String value = getString(columnName);
-        return isNotBlank(value) ? Integer.parseInt(value.trim()) : 0;
+        return isNotBlank(value) ? Integer.parseInt(value.trim()) : null;
     }
 
     BigDecimal getBigDecimal(final String columnName) {
diff --git a/src/test/java/net/hostsharing/hsadminng/hs/migration/ImportHostingAssets.java b/src/test/java/net/hostsharing/hsadminng/hs/migration/ImportHostingAssets.java
index dda271f2..37040b6b 100644
--- a/src/test/java/net/hostsharing/hsadminng/hs/migration/ImportHostingAssets.java
+++ b/src/test/java/net/hostsharing/hsadminng/hs/migration/ImportHostingAssets.java
@@ -356,6 +356,10 @@ public class ImportHostingAssets extends ImportOfficeData {
                     final var old_inet_addr_id = rec.getInteger("old_inet_addr_id"); // FIXME: assert that null
                     final var free = rec.getBoolean("free"); // FIXME: assert that "free webspace => in customer managed server", otherwise ignore
 
+                    assertThat(old_inet_addr_id)
+                            .as("packet.old_inet_addr_id not supported, but is not null for " + packet_name)
+                            .isNull();
+
                     final var biType = determineBiType(basepacket_code);
                     final var bookingItem = HsBookingItemEntity.builder()
                             .type(biType)
@@ -366,6 +370,10 @@ public class ImportHostingAssets extends ImportOfficeData {
                     bookingItems.put(PACKET_ID_OFFSET + packet_id, bookingItem);
 
                     final var haType = determineHaType(basepacket_code);
+                    assertThat(!free || haType == MANAGED_WEBSPACE || bookingItem.getRelatedProject().getDebitor().getDefaultPrefix().equals("hsh"))
+                            .as("packet.free only supported for Hostsharing-Assets and ManagedWebspace in customer-ManagedServer, but is set for " + packet_name)
+                            .isTrue();
+
                     final var asset = HsHostingAssetEntity.builder()
                             .isLoaded(haType == MANAGED_WEBSPACE) // this turns off identifier validation to accept former default prefixes
                             .type(haType)