What's new in PHP 8.1 - behind the scenes

Internal property reflection

• Almost all internal properties became declared

  • ​https://3v4l.org/KO4bo

• A few properties became readonly

• Almost all properties became typed

Documentation Improvements

• Stubs are being synchronized with the documentation
  • https://github.com/php/doc-en/issues?q=label%3A%22method+synopsis%22+is%3Aclosed
• Formatting changes
  • https://web.archive.org/web/20201001061103/https://www.php.net/manual/en/class.domdocument.php
  • https://www.php.net/manual/en/class.domdocument.php

Resource to Object Conversion

There are only 6 extensions left which still expose resources

• fileinfo (fixed in PHP 8.1)

• FTP (fixed in PHP 8.1)

• GD (fixed in PHP 8.1)

• IMAP (fixed in PHP 8.1)

• LDAP (fixed in PHP 8.1)

• pgsql (fixed in PHP 8.1)

• pspell (fixed in PHP 8.1)

• com

• DBA

• OCI8

• ODBC

• SOAP (partly fixed in PHP 8.1)

• standard

https://github.com/php/php-tasks/issues/6

mbstring refactor

OPCache improvements

• JIT for ARM64 architecture
• Inheritance cache
  • https://externals.io/message/113091
• Fast class cache
  • https://github.com/php/php-src/pull/6843
• Generated and extended return type information for inference
• Tons of type inference fixes

Performance improvements

https://github.com/kocsismate/php-version-benchmarks/blob/main/docs/results/2021_11_25_10_08_1_aws_arm64_c6g_4xlarge/result.md​