Performed the WordPress core update to 4.8 which was successful, then performed the update from Marketpess 3.1.1 to 3.2.4 which said it was successful but upon visiting the front end of the site saw the error:
WordPress database error: [Incorrect index name '']
ALTER TABLE wp_arts_mp_term_relationships ADD KEY
term_id) /* From [artsactivities.staging.wpengine.com/] in [/nas/content/staging/artsactivities/wp-content/plugins/marketpress/includes/common/class-mp-installer.php:1248] */
This was performed on a WP Engine staging deployment of the live site (https://artsandactivities.com). The staging version of the live site (where the Marketpress update was performed) can be seen here: http://artsactivities.staging.wpengine.com I have activated WPMU Dev Dashboard Access to the staging site.