Wordpress markdown.php Unknown modifier ‘|’

So all of a sudden, all the posts started showing preg_replace_callback() [function.preg-replace-callback]: Unknown modifier ‘|’ in …/wp-content/plugins/text-control/markdown.php. I presume this was because my provider changed php versions. There are 2 possible fixes:

1. Disable your markdown plugin
2. Fix the markdown.php file, if you can edit it. This problem was a couple of lines above the one reported, one of the opening braces (“{“) had a back-slash quote where it should not have. ie, it was …(?:[ ]\{$md_tab_width}… but shold just be …(?:[ ]{$md_tab_width}…