*/
    static Stream<Arguments> messages() {
        return Stream.of(Arguments.of((String) null), Arguments.of(""), Arguments.of("unexpected downgrade"));
    }

    @Test
    @DisplayName("Default ctor: null message/cause; toString is class name; type hierarchy")
    void defaultConstructor_hasNullMessageAndCause_andTypeHierarchy() {
        // Arrange & Act

 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
 */
package jcifs.smb;

import jcifs.CIFSException;

/**
 * Exception thrown when an SMB protocol downgrade attack is detected.
 * Indicates that the negotiated protocol version is lower than expected or required.
 *
 * @author mbechler
 *
 */
public class SMBProtocolDowngradeException extends CIFSException {

    /**

import jcifs.internal.smb2.nego.PreauthIntegrityNegotiateContext;

/**
 * Enhanced Pre-Authentication Integrity Service for SMB 3.1.1.
 *
 * Provides comprehensive pre-authentication integrity protection against
 * downgrade attacks by maintaining cryptographic hash chains of all
 * negotiation and session setup messages.
 */
public class PreauthIntegrityService {

- **Encryption Context**: Per-session encryption state management
- **Key Derivation**: SMB3 KDF implementation with dialect-specific parameters
- **Pre-Authentication Integrity**: SMB 3.1.1 PAI for preventing downgrade attacks
- **Automatic Detection**: Encryption automatically enabled when servers require it
- **Secure Key Management**: Proper key derivation and nonce generation

### Core Features

            assertEquals("package", packageExecution.child("phase").orElse(null).textContent());
        }
    }

    @Nested
    @DisplayName("Downgrade Handling")
    class DowngradeHandlingTests {

        @Test
        @DisplayName("should fail with error when attempting downgrade from 4.1.0 to 4.0.0")
        void shouldFailWhenAttemptingDowngrade() throws Exception {
            String pomXml = """

import jcifs.internal.util.SMBUtil;

/**
 * SMB2 Pre-authentication Integrity Negotiate Context.
 *
 * This negotiate context is used in SMB 3.1.1 to establish
 * pre-authentication integrity protection against downgrade attacks.
 *
 * @author mbechler
 */
public class PreauthIntegrityNegotiateContext implements NegotiateContextRequest, NegotiateContextResponse {

    /**
     * Context type
     */

  fun wrongConnectionHeader() {
    webServer.enqueue(
      MockResponse
        .Builder()
        .code(101)
        .setHeader("Upgrade", "websocket")
        .setHeader("Connection", "Downgrade")
        .setHeader("Sec-WebSocket-Accept", "ujmZX4KXZqjwy6vi1aQFH5p4Ygk=")
        .build(),
    )
    webServer.enqueue(
      MockResponse
        .Builder()
        .onRequestStart(CloseSocket())

- [ ] Implement lease key generation and management
- [ ] Add lease context to Create request/response
- [ ] Implement lease break notification handling
- [ ] Modify SmbFile to support lease-based caching
- [ ] Add lease upgrade/downgrade logic
- [ ] Implement lease epoch tracking for v2 leases

#### 1.3 Integration Points
- Modify `Smb2CreateRequest` to include lease contexts
- Update `SmbFile` caching logic to use leases

        }

        @ParameterizedTest(name = "from {0} to {1}")
        @MethodSource("provideInvalidPathUpgradeVersions")
        @DisplayName("should reject downgrade")
        void shouldRejectDowngrade(String from, String to) {
            assertFalse(ModelVersionUtils.canUpgrade(from, to));
        }

        private static Stream<Arguments> provideInvalidPathUpgradeVersions() {

		case madmin.AdminAPIVersion:
			desc = fmt.Sprintf("This 'admin' API is not supported by server in '%s'", getMinioMode())
		default:
			desc = fmt.Sprintf("Unexpected client 'admin' API version found '%s', expected '%s', please downgrade the client to older releases", version, madmin.AdminAPIVersion)
		}
		writeErrorResponseJSON(r.Context(), w, APIError{
			Code:           "XMinioAdminVersionMismatch",
			Description:    desc,