Default value of the $flag argument changed in PHP 8.1 from ENT_COMPAT to ENT_QUOTES | ENT_SUBSTITUTE
To ensure consistent behavior across different PHP version the second parameter is now required for the functions:
htmlspecialchars(), htmlentities(), htmlspecialchars_decode(), html_entity_decode() and get_html_translation_table()
Before the patch, transliteration was only happening when the
encoding of the string was utf-8. For other encodings only a
simpler conversion (iconv) to ascii was done. For some reason
iconv() own transliteration abilities are not consistent
between systems (depends of libraries installed, locales and
other bits).
So now we always convert the string to utf-8, in order to
transliterate it. And finally, also perform an iconv to
cover some characters that transliterate doesn't handle ok.
Also, remove a block of code that does nothing (previously
it was executing some code, but now it just sets and restores
the error level for nothing).
Add option to class csv_export_writer to prefix CSV file with UTF-8 byte
order mark (BOM). This helps Microsoft Excel detect the file's character
encoding.
Four core library classes renamed for autoloading with deprecated stubs
have been converted to the new scheme for autoloading.
They are:
* textlib
* collatorlib
* plugin_manager
* plugininfo_base
These will be removed in 2.9 by MDL-46124
