Fatal error

Tried to add a blog post and got this message. Checked the file but there is no line 544 only goes to 276.

Fatal error: Class 'ParsedownExtra' not found in /home4/digitale/public_html/perch/core/lib/PerchFieldTypes.class.php on line 544.

Perch Runway: 2.8.15, PHP: 5.5.30, MySQL: mysqlnd 5.0.11-dev - 20120503 - $Id: 15d5c781cfcad91193dceae1d2cdd127674ddb3e $, with PDO
Server OS: Linux, cgi-fcgi
Installed apps: content (2.8.15), assets (2.8.15), categories (2.8.15), perch_blog (4.6), perch_kraken (1.0), perch_mailchimp (2.0.1), collection_1 (2.8.15), perch_backup (1.2)
App runtimes: <?php $apps_list = array( 'content', 'categories', 'perch_blog', 'perch_mailchimp', );
PERCH_LOGINPATH: /perch
PERCH_PATH: /home4/digitale/public_html/perch
PERCH_CORE: /home4/digitale/public_html/perch/core
PERCH_RESFILEPATH: /home4/digitale/public_html/perch/resources
Image manipulation: GD Imagick
PHP limits: Max upload 128M, Max POST 128M, Memory: 128M, Total max file upload: 128M
Resource folder writeable: Yes
SCRIPT_NAME: /perch/core/settings/diagnostics/index.php
REQUEST_URI: /perch/core/settings/diagnostics/
DOCUMENT_ROOT: /home4/digitale/public_html
HTTP_HOST: digitaleducation.education