The RFC proposes to deprecate the listed functionality in PHP 8.1 and remove it in PHP 9.
Deprecate date_sunrise() and date_sunset()?
Deprecate key(), current(), next(), prev(), reset() on objects?
Deprecate mb_check_encoding() without argument?
Deprecate get_class(), get_parent_class() and get_called_class() without argument?
Deprecate FILE_BINARY and FILE_TEXT constants?
Deprecate passing bool for $value argument of IntlCalendar::roll()?
Deprecate accessing static members on traits?
Deprecate strftime() and gmstrftime()?
Deprecate mhash*() family of functions?
Deprecate int parameters to ctype_*() functions?
Deprecate return by reference with void type?
Deprecate NIL constant defined by the IMAP extension?
Deprecate calling overloaded pgsql functions without the connection argument?
Deprecate $num_points parameter of image(open|filled)polygon?
Deprecate mysqli::init()?
Deprecate filter.default ini setting?
Deprecate auto_detect_line_endings ini setting?
Deprecate ssl_method option to SoapClient constructor?
Deprecate FILTER_SANITIZE_STRING?
Deprecate oci8.old_oci_close_semantics INI setting?
Deprecate odbc_result_all()?