Remove redundant isofield with id 96

jpos/src/main/resources/packager/cmf-858.xml

@@ -763,7 +763,7 @@
       name="Reserved for ISO use"
       pad="false"
       class="org.jpos.iso.IFB_LLLLBINARY"/>
-  <isofield id="96"
+  <isofield id="91"
       length="9999"
       name="Reserved for ISO use"
       pad="false"

jpos/src/main/resources/packager/cmf.xml

@@ -763,7 +763,7 @@
       name="Reserved for ISO use"
       pad="false"
       class="org.jpos.iso.IFB_LLLLBINARY"/>
-  <isofield id="96"
+  <isofield id="91"
       length="9999"
       name="Reserved for ISO use"
       pad="false"

jpos/src/main/resources/packager/cmfv3.xml

@@ -776,11 +776,11 @@
       name="Reserved for ISO use"
       pad="false"
       class="org.jpos.iso.IFB_LLLLBINARY"/>
-  <isofield id="96"
-      length="999"
-      name="Key management data"
+  <isofield id="91"
+      length="9999"
+      name="Reserved for ISO use"
       pad="false"
-      class="org.jpos.iso.IFB_LLLBINARY"/>
+      class="org.jpos.iso.IFB_LLLLBINARY"/>
   <isofield id="92"
       length="9999"
       name="Reserved for ISO use"

jpos/src/test/java/org/jpos/iso/packager/CMFFieldDefinitionsTest.java

@@ -0,0 +1,103 @@
+/*
+ * jPOS Project [http://jpos.org]
+ * Copyright (C) 2000-2026 jPOS Software SRL
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU Affero General Public License as
+ * published by the Free Software Foundation, either version 3 of the
+ * License, or (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU Affero General Public License for more details.
+ *
+ * You should have received a copy of the GNU Affero General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+package org.jpos.iso.packager;
+
+import java.io.InputStream;
+import java.util.Arrays;
+import java.util.HashSet;
+import java.util.Set;
+import javax.xml.parsers.DocumentBuilderFactory;
+
+import org.jpos.iso.IFB_LLLBINARY;
+import org.jpos.iso.IFB_LLLLBINARY;
+import org.jpos.iso.ISOBinaryField;
+import org.jpos.iso.ISOFieldPackager;
+import org.jpos.iso.ISOMsg;
+import org.junit.jupiter.params.ParameterizedTest;
+import org.junit.jupiter.params.provider.ValueSource;
+import org.w3c.dom.Element;
+import org.w3c.dom.Node;
+
+import static org.junit.jupiter.api.Assertions.assertArrayEquals;
+import static org.junit.jupiter.api.Assertions.assertEquals;
+import static org.junit.jupiter.api.Assertions.assertInstanceOf;
+import static org.junit.jupiter.api.Assertions.assertNotNull;
+import static org.junit.jupiter.api.Assertions.assertTrue;
+
+class CMFFieldDefinitionsTest {
+    @ParameterizedTest
+    @ValueSource(strings = {"cmf.xml", "cmfv3.xml", "cmf-858.xml"})
+    void topLevelFieldIdsAreUnique(String resource) throws Exception {
+        DocumentBuilderFactory factory = DocumentBuilderFactory.newInstance();
+        factory.setFeature("http://xml.org/sax/features/external-general-entities", false);
+        factory.setFeature("http://xml.org/sax/features/external-parameter-entities", false);
+        factory.setFeature("http://apache.org/xml/features/nonvalidating/load-external-dtd", false);
+        try (InputStream input = resource(resource)) {
+            Element root = factory.newDocumentBuilder().parse(input).getDocumentElement();
+            Set<String> ids = new HashSet<>();
+            for (Node child = root.getFirstChild(); child != null; child = child.getNextSibling()) {
+                if (child instanceof Element field && field.hasAttribute("id"))
+                    assertTrue(ids.add(field.getAttribute("id")),
+                        resource + ": duplicate field " + field.getAttribute("id"));
+            }
+        }
+    }
+
+    @ParameterizedTest
+    @ValueSource(strings = {"cmf.xml", "cmfv3.xml", "cmf-858.xml"})
+    void reservedAndKeyManagementFieldsRoundTripAtTheirLimits(String resource) throws Exception {
+        GenericPackager packager;
+        try (InputStream input = resource(resource)) {
+            packager = new GenericPackager(input);
+        }
+        ISOFieldPackager reserved = packager.getFieldPackager(91);
+        ISOFieldPackager keys = packager.getFieldPackager(96);
+        assertInstanceOf(IFB_LLLLBINARY.class, reserved);
+        assertEquals(9999, reserved.getLength());
+        assertInstanceOf(IFB_LLLBINARY.class, keys);
+        assertEquals(999, keys.getLength());
+
+        byte[] reservedData = new byte[9999];
+        byte[] keyData = new byte[999];
+        Arrays.fill(reservedData, (byte) 0xA5);
+        Arrays.fill(keyData, (byte) 0x5A);
+        assertArrayEquals(new byte[] {(byte) 0x99, (byte) 0x99},
+            Arrays.copyOf(reserved.pack(new ISOBinaryField(91, reservedData)), 2));
+        assertArrayEquals(new byte[] {0x09, (byte) 0x99},
+            Arrays.copyOf(keys.pack(new ISOBinaryField(96, keyData)), 2));
+
+        ISOMsg message = new ISOMsg();
+        message.setPackager(packager);
+        message.setMTI("1200");
+        message.set(91, reservedData);
+        message.set(96, keyData);
+        byte[] packed = message.pack();
+        ISOMsg unpacked = new ISOMsg();
+        unpacked.setPackager(packager);
+        assertEquals(packed.length, unpacked.unpack(packed));
+        assertArrayEquals(reservedData, unpacked.getBytes(91));
+        assertArrayEquals(keyData, unpacked.getBytes(96));
+    }
+
+    private InputStream resource(String name) {
+        InputStream input = getClass().getResourceAsStream("/packager/" + name);
+        assertNotNull(input, name);
+        return input;
+    }
+}