Re: 2.5.10 - User profile won
No, try changing the line 51 to:
KEY `sort` (`step_order`, `step_name`(240))
The issue is with the MySQL key length limitations: it's 767 bytes is the stated prefix limitation for InnoDB tables in MySQL version 5.6 (and prior versions). It's 1,000 bytes long for MyISAM tables.
In MySQL version 5.7 and upwards this limit has been increased to 3072 bytes.
The indexes worked fine with utf8_unicode_ci, since it uses 3 bytes per character, but when you're using utf8mb4_unicode_ci, you're adding extra byte, as it is using 4 bytes, and you're going over the limit.
MySQL 5.7 avoids the problem. Consider upgrading