UPGRADING

PHP 8.1 UPGRADE NOTES

1. Backward Incompatible Changes
2. New Features
3. Changes in SAPI modules
4. Deprecated Functionality
5. Changed Functions
6. New Functions
7. New Classes and Interfaces
8. Removed Extensions and SAPIs
9. Other Changes to Extensions
10. New Global Constants
11. Changes to INI File Handling
12. Windows Support
13. Other Changes
14. Performance Improvements

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1. Backward Incompatible Changes
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- Core:
  . Access to the $GLOBALS array is now subject to a number of restrictions.
    Read and write access to individual array elements like $GLOBALS['var']
    continues to work as-is. Read-only access to the entire $GLOBALS array also
    continues to be supported. However, write access to the entire $GLOBALS
    array is no longer supported. For example, array_pop($GLOBALS) will result
    in an error.
    RFC: https://wiki.php.net/rfc/restrict_globals_usage

- Fileinfo:
  . The fileinfo functions now accept and return, respectively, finfo objects
    instead of resources.

- IMAP:
  . The IMAP functions now accept and return, respectively, IMAPConnection objects
    instead of resources.

- MySQLi:
  . mysqli_fetch_fields() and mysqli_fetch_field_direct() will now always return
    zero for max_length. You can compute this information by iterating over the
    result set and taking the maximum length. This is what PHP was doing
    internally previously.
  . The MYSQLI_STMT_ATTR_UPDATE_MAX_LENGTH option no longer has an effect.
  . The MYSQLI_STORE_RESULT_COPY_DATA option no longer has an effect.

- MySQLnd:
  . The mysqlnd.fetch_copy_data ini setting has been removed. However, this
    should not result in user-visible behavior changes.

- PDO:
  . PDO::ATTR_STRINGIFY_FETCHES now also stringifies values of type bool to
    "0" or "1". Previously booleans were not stringified.
  . Calling bindColumn() with PDO::PARAM_LOB (and assuming stringification is
    not enabled) will now consistently bind a stream result, as documented.
    Previously the result would be either a stream or a string depending on the
    used database driver and the time the binding is performed.

- PDO MySQL:
  . Integers and floats in result sets will now be returned using native PHP
    types instead of strings when using emulated prepared statements. This
    matches the behavior of native prepared statements. You can restore the
    previous behavior by enabling the PDO::ATTR_STRINGIFY_FETCHES option.

- PDO SQLite:
  . Integers and floats in results sets will now be returned using native PHP
    types. You can restore the previous behavior by enabling the
    PDO::ATTR_STRINGFIY_FETCHES option.

- Standard:
  . version_compare() no longer accepts undocumented operator abbreviations.
  . htmlspecialchars(), htmlentities(), htmlspecialchars_decode(),
    html_entitity_decode() and get_html_translation_table() now use
    ENT_QUOTES | ENT_SUBSTITUTE rather than ENT_COMPAT by default. This means
    that ' is escaped to ' while previously it was left alone.
    Additionally, malformed UTF-8 will be replaced by a Unicode substitution
    character, instead of resulting in an empty string.

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2. New Features
========================================

- Core:
  . It is now possible to specify octal integer by using the explicit "0o"/"0O"
    prefix similar to hexadecimal ("0x"/"0X) and binary ("0b"/"0B") integer literals
    RFC: https://wiki.php.net/rfc/explicit_octal_notation

- Curl:
  . Added CURLOPT_DOH_URL option.

- hash:
  . The following functions have changed signatures:

    - function hash(string $algo, string $data, bool $binary = false, array $options = []): string|false {}
    - function hash_file(string $algo, string $filename, bool $binary = false, array $options = []): string|false {}
    - function hash_init(string $algo, int $flags = 0, string $key = "", array $options = []): HashContext {}

    The additional `$options` argument can be used to pass algorithm specific data.

  . Added MurmurHash3 with streaming support. The following variants are implemented:

    - murmur3a, 32-bit hash
    - murmur3c, 128-bit hash for x86
    - murmur3f, 128-bit hash for x64

    The initial hash state can be passed through the `seed` key in the `$options` array, for example:

    ```php
    $h = hash("murmur3f", $data, options: ["seed" => 42]);
    echo $h, "\n";
    ```

    A valid seed value is within the range from 0 to the plaform defined UINT_MAX, usually 4294967295.

  . Added xxHash. The implementation brings in the following arguments

    - xxh32, 32-bit hash
    - xxh64, 64-bit hash
    - xxh3, 64-bit hash
    - xxh128, 128-bit hash

    The initial hash state can be passed through the `seed` key in the `$options` array, for example:

    ```php
    $h = hash("xxh3", $data, options: ["seed" => 42]);
    echo $h, "\n";
    ```

- Posix:
  . Added POSIX_RLIMIT_KQUEUES and POSIX_RLIMIT_NPTS. These rlimits are only
    available on FreeBSD.

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3. Changes in SAPI modules
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4. Deprecated Functionality
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5. Changed Functions
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- Filter:
  . The FILTER_FLAG_ALLOW_OCTAL flag of the FILTER_VALIDATE_INT filter now accept
    octal string with the leading octal prefix ("0o"/"0O")
    RFC: https://wiki.php.net/rfc/explicit_octal_notation

- GMP:
  . All GMP function now accept octal string with the leading octal prefix ("0o"/"0O")
    RFC: https://wiki.php.net/rfc/explicit_octal_notation

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6. New Functions
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7. New Classes and Interfaces
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========================================
8. Removed Extensions and SAPIs
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9. Other Changes to Extensions
========================================

- MySQLi:
  . The mysqli_stmt::next_result() and mysqli::fetch_all() methods are now
    available when linking against libmysqlclient.

- OpenSSL:
  . The OpenSSL extension now requires at least OpenSSL version 1.0.2.

- Standard:
  . --with-password-argon2 now uses pkg-config to detect libargon2. As such,
    an alternative libargon2 location should now be specified using
    PKG_CONFIG_PATH.

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10. New Global Constants
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11. Changes to INI File Handling
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12. Windows Support
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. The macro IGNORE_URL_WIN has been removed; it had no effect as of PHP 5.0.0.

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13. Other Changes
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14. Performance Improvements
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