PHP 7.3 Flexible Heredoc Continue in Switch List References Trailing comma allowed in function calls New Monotonic Timer function print_r(hrtime()); Array ( [0] => 2320165 // seconds [1] => 979969517 // nanoseconds ) php > print_r(hrtime(true)); 2320183081647424 ]]> New fpm_get_status() function www [process-manager] => static [start-time] => 1536934549 [start-since] => 26 [accepted-conn] => 20039 [listen-queue] => 0 [max-listen-queue] => 0 [listen-queue-len] => 0 [idle-processes] => 0 [active-processes] => 47 [total-processes] => 47 [max-active-processes] => 514 [max-children-reached] => 0 [slow-requests] => 0 [procs] => Array ( [0] => Array ( [pid] => 10819 [state] => Running [start-time] => 1536934549 [start-since] => 26 [requests] => 2001 [request-duration] => 8108 [request-method] => GET [request-uri] => /index.php [query-string] => p=1 [request-length] => 0 [user] => - [script] => /var/www/wordpress/index.php [last-request-cpu] => 0 [last-request-memory] => 0 ) ... ]]> is_countable() array_key_first()/array_key_last() 'First', 'def'=>'Second', 'ghi'=>'Third']; echo array_key_first($a); // abc echo array_key_last($a); // ghi ]]> More DCE and SCCP optimizations Other changes Upgraded from PCRE to PCRE2 getallheaders() now available in php-fpm full case-mapping for mbstring preg_quote() now also escapes '#' new gmp functions: gmp_binomial, gmp_lcm, gmp_perfect_power, gmp_kronecker new JsonException default ftp transfer mode is now binary Things that may break your code PCRE2 differences (should be rare) ODBCRouter and Birdstep support have been removed Various deprecations - see UPGRADING Full details are at: And for extension authors: