perl5311delta - what is new for perl v5.31.1


This document describes differences between the 5.31.0 release and the 5.31.1 release.

If you are upgrading from an earlier release such as 5.30.0, first read perl5310delta, which describes differences between 5.30.0 and 5.31.0.

Incompatible Changes

Use of vec on strings with code points above 0xFF is forbidden

Such strings are represented internally in UTF-8, and vec is a bit-oriented operation that will likely give unexpected results on those strings. This was deprecated in perl 5.28.0.

Use of code points over 0xFF in string bitwise operators

Some uses of these were already illegal after a previous deprecation cycle. The remaining uses are now prohibited, having been deprecated in perl 5.28.0. See perldeprecation.

Sys::Hostname::hostname() does not accept arguments

This usage was deprecated in perl 5.28.0 and is now fatal.

Modules and Pragmata

Updated Modules and Pragmata

Removed Modules and Pragmata


Changes to Existing Documentation

We have attempted to update the documentation to reflect the changes listed in this document. If you find any we have missed, send email to

Additionally, the following selected changes have been made:



Configuration and Compilation

Platform Support

Discontinued Platforms

Windows CE

Support for building perl on Windows CE has now been removed.

Internal Changes

Selected Bug Fixes


Perl 5.31.1 represents approximately 4 weeks of development since Perl 5.31.0 and contains approximately 37,000 lines of changes across 500 files from 20 authors.

Excluding auto-generated files, documentation and release tools, there were approximately 19,000 lines of changes to 340 .pm, .t, .c and .h files.

Perl continues to flourish into its fourth decade thanks to a vibrant community of users and developers. The following people are known to have contributed the improvements that became Perl 5.31.1:

Alexandr Savca, Andreas König, Chris 'BinGOs' Williams, Dagfinn Ilmari Mannsåker, Dominic Hargreaves, Graham Knop, Hugo van der Sanden, James E Keenan, Jerome Duval, Karen Etheridge, Karl Williamson, Manuel Mausz, Michael Haardt, Nicolas R., Pali, Richard Leach, Sawyer X, Steve Hay, Tony Cook, Vickenty Fesunov.

The list above is almost certainly incomplete as it is automatically generated from version control history. In particular, it does not include the names of the (very much appreciated) contributors who reported issues to the Perl bug tracker.

Many of the changes included in this version originated in the CPAN modules included in Perl's core. We're grateful to the entire CPAN community for helping Perl to flourish.

For a more complete list of all of Perl's historical contributors, please see the AUTHORS file in the Perl source distribution.

Reporting Bugs

If you find what you think is a bug, you might check the perl bug database at There may also be information at, the Perl Home Page.

If you believe you have an unreported bug, please run the perlbug program included with your release. Be sure to trim your bug down to a tiny but sufficient test case. Your bug report, along with the output of perl -V, will be sent off to to be analysed by the Perl porting team.

If the bug you are reporting has security implications which make it inappropriate to send to a publicly archived mailing list, then see "SECURITY VULNERABILITY CONTACT INFORMATION" in perlsec for details of how to report the issue.

Give Thanks

If you wish to thank the Perl 5 Porters for the work we had done in Perl 5, you can do so by running the perlthanks program:


This will send an email to the Perl 5 Porters list with your show of thanks.


The Changes file for an explanation of how to view exhaustive details on what changed.

The INSTALL file for how to build Perl.

The README file for general stuff.

The Artistic and Copying files for copyright information.