if (decoded != normalizeNfc(decoded)) return null

  // TODO: Must not begin with a combining mark.
  // TODO: Each character must be 'valid' or 'deviation'. Not mapped.
  // TODO: CheckJoiners from IDNA 2008
  // TODO: CheckBidi from IDNA 2008, RFC 5893, Section 2.

  return Punycode.encode(decoded)

    returned.

 *  Upgrade: [Okio 3.9.0][okio_3_9_0].

 *  Upgrade: [Kotlin 1.9.23][kotlin_1_9_23].

 *  Upgrade: [Unicode® IDNA 15.1.0][idna_15_1_0]


## Version 5.0.0-alpha.12

_2023-12-17_

We took too long to cut this release and there's a lot of changes in it. We've been busy.

          "co\uFF61uk", // Alternate dot character
          "\u7f51\u7edc.Cn", // "网络.Cn"
          "j\u00f8rpeland.no", // "jorpeland.no" (first o slashed)
          "xn--jrpeland-54a.no"); // IDNA (punycode) encoding of above

  private static final ImmutableSet<String> PS_NOT_RS =
      ImmutableSet.of("blogspot.com", "blogspot.co.uk", "uk.com");

  private static final ImmutableSet<String> PS =

    pip install altgraph appdirs cachetools certifi cffi chardet colorama \
    cryptography cycler Cython decorator google-api-python-client \
    google-auth google-auth-httplib2 grpcio httplib2 idna ipython-genutils \
    kiwisolver macholib matplotlib nose numpy packaging pandas pickleshare pip \
    prompt-toolkit protobuf psutil pyasn1 pyasn1-modules pycparser Pygments \

          "co\uFF61uk", // Alternate dot character
          "\u7f51\u7edc.Cn", // "网络.Cn"
          "j\u00f8rpeland.no", // "jorpeland.no" (first o slashed)
          "xn--jrpeland-54a.no"); // IDNA (punycode) encoding of above

  private static final ImmutableSet<String> PS_NOT_RS =
      ImmutableSet.of("blogspot.com", "blogspot.co.uk", "uk.com");

  private static final ImmutableSet<String> PS =

    --hash=sha256:fd6f6d1384a9f491732cee233b99cd4bfd6e838a8815cc86722f9d2ee64032af
    # via
    #   -r requirements.in
    #   keras-nightly
idna==3.7 \
    --hash=sha256:028ff3aadf0609c1fd278d8ea3089299412a7a8b9bd005dd08b9f8285bcb5cfc \
    --hash=sha256:82fee1fc78add43492d3a1898bfa6d8a904cc97d8427f683ed8e798d07761aa0
    # via requests
jax==0.4.7 \

    --hash=sha256:fd6f6d1384a9f491732cee233b99cd4bfd6e838a8815cc86722f9d2ee64032af
    # via
    #   -r requirements.in
    #   keras-nightly
idna==3.7 \
    --hash=sha256:028ff3aadf0609c1fd278d8ea3089299412a7a8b9bd005dd08b9f8285bcb5cfc \
    --hash=sha256:82fee1fc78add43492d3a1898bfa6d8a904cc97d8427f683ed8e798d07761aa0
    # via requests
jax==0.4.7 \

    --hash=sha256:fd6f6d1384a9f491732cee233b99cd4bfd6e838a8815cc86722f9d2ee64032af
    # via
    #   -r requirements.in
    #   keras-nightly
idna==3.7 \
    --hash=sha256:028ff3aadf0609c1fd278d8ea3089299412a7a8b9bd005dd08b9f8285bcb5cfc \
    --hash=sha256:82fee1fc78add43492d3a1898bfa6d8a904cc97d8427f683ed8e798d07761aa0
    # via requests
importlib-metadata==7.0.1 \

    --hash=sha256:fd6f6d1384a9f491732cee233b99cd4bfd6e838a8815cc86722f9d2ee64032af
    # via
    #   -r requirements.in
    #   keras-nightly
idna==3.7 \
    --hash=sha256:028ff3aadf0609c1fd278d8ea3089299412a7a8b9bd005dd08b9f8285bcb5cfc \
    --hash=sha256:82fee1fc78add43492d3a1898bfa6d8a904cc97d8427f683ed8e798d07761aa0
    # via requests
jax==0.4.7 \

 * names</a> such as {@code 网络.cn} are supported, as are the equivalent <a
 * href="http://en.wikipedia.org/wiki/Internationalized_domain_name">IDNA Punycode-encoded</a>
 * versions.
 *
 * @author Catherine Berry
 * @since 5.0
 */
@GwtCompatible(emulated = true)
@Immutable
@ElementTypesAreNonnullByDefault
public final class InternetDomainName {