* @deprecated NTLMv1 is insecure. Use NTLMv2 (LM compatibility level 3 or higher)
     */
    @Deprecated
    public byte[] getAnsiHash(CIFSContext tc, byte[] chlng) throws GeneralSecurityException {
        int compatibility = tc.getConfig().getLanManCompatibility();

        // Log warning for insecure NTLMv1 usage
        if (compatibility < 3) {

with Java.

We spent a lot of time and energy on retaining strict compatibility with OkHttp 3.x. We’re even
keeping the package name the same: `okhttp3`!

There are three kinds of compatibility we’re tracking:

 * **Binary compatibility** is the ability to compile a program against OkHttp 3.x, and then to run

        if (lmCompatibility == 3 || lmCompatibility == 4 || lmCompatibility == 5) {
            // For LM compatibility 3-5, only 16 bytes are used
            doAnswer(invocation -> {
                byte[] dest = invocation.getArgument(2);
                int offset = invocation.getArgument(3);
                System.arraycopy(new byte[16], 0, dest, offset, 16);
                return null;

            if (stage.specificBuilds.contains(SpecificBuild.SanityCheck)) {
                buildReportTab(
                    "API Compatibility Report",
                    "$HIDDEN_ARTIFACT_DESTINATION/report-architecture-test-binary-compatibility-report.html",
                )
                buildReportTab("Incubating APIs Report", "incubation-reports/all-incubating.html")
            }

2. **Multi-Channel Synchronization**: Complex thread synchronization required
3. **Persistent Handle State**: Requires reliable state persistence mechanism
4. **Backward Compatibility**: Must maintain compatibility with SMB2/SMB1

### Mitigation Strategies
1. Implement features behind configuration flags
2. Provide graceful fallback mechanisms
3. Extensive testing with various server configurations

---
title: "Go, Backwards Compatibility, and GODEBUG"
layout: article
---

<!--
This document is kept in the Go repo, not x/website,
because it documents the full list of known GODEBUG settings,
which are tied to a specific release.
-->

## Introduction {#intro}

Go's emphasis on backwards compatibility is one of its key strengths.
There are, however, times when we cannot maintain complete compatibility.

   * situations for compatibility.
   *
   * @since 17.0
   */
  public static final MediaType WOFF = createConstant(APPLICATION_TYPE, "font-woff");

  /**
   * <a href="https://tools.ietf.org/html/rfc8081">RFC 8081</a> declares {@link #FONT_WOFF2
   * font/woff2} to be the correct media type for WOFF2, but this may be necessary in certain
   * situations for compatibility.
   *
   * @since 20.0
   */

            assertEquals(error, exception.getCause());
        });
    }

    @Test
    @DisplayName("Should maintain serialization compatibility")
    void testSerialization() {
        // Verify the class has serialVersionUID defined
        // This is important for version compatibility
        RuntimeCIFSException exception = new RuntimeCIFSException("Test");

     * @return default credentials, password
     */
    String getDefaultPassword();

    /**
     * Lanman compatibility level
     *
     * <a href="https://technet.microsoft.com/en-us/library/cc960646.aspx">Microsoft TechNet Documentation</a>
     *
     *
     * <table>
     * <caption>LM Compatibility Levels</caption>
     * <tr>
     * <td>0 or 1</td>
     * <td>LM and NTLM</td>
     * </tr>
     * <tr>

   * situations for compatibility.
   *
   * @since 17.0
   */
  public static final MediaType WOFF = createConstant(APPLICATION_TYPE, "font-woff");

  /**
   * <a href="https://tools.ietf.org/html/rfc8081">RFC 8081</a> declares {@link #FONT_WOFF2
   * font/woff2} to be the correct media type for WOFF2, but this may be necessary in certain
   * situations for compatibility.
   *
   * @since 20.0
   */