I know, the world is divided between php7 and non php7 users. My most stable system I use php 5.3.5, but some plugins begin to not work anymore.
Maybe it could be a good idea to insert in DW the download button in two sections: ante and post php7. I bet that in 2029 30%from users like me will still use php 5.6, or even lower..
Please update topbarsyntax Plugin for PHP 7.3, changing at least the following lines in Syntax.php
function handle($match, $state, $pos, &$handler
in
function handle($match, $state, $pos, Doku_Handler $handler
si
function render($mode, &$renderer, $data
in
function render($mode, Doku_Renderer $renderer, $data