I'm using WP Sync DB plugin for migrating sites between dev, stage and live. Recently i ran in this problem: while creating a new instance on my local dev, WordPress created all tables with utf8mb4_unicode_ci. This leads to problems getting the data migrated. Also live servers often don't support utf8mb4 at all.
I already set
define('DB_COLLATE', 'utf8_general_ci'); but WordPress ignoredt it on creation.