Question: I’m developing a site locally on XAMPP with SQL 5.6.21. When I attempt to import the database to a server using an older version of SQL I get the following error: “#1273 – Unknown collation: ‘utf8mb4_unicode_ci’”
Answer: That’s not exactly a WordPress problems, and it would be easier to upgrade MySQL on the server, to be honest.
You need MySQL 5.5.3 or higher to support the utf8mb4_unicode_ci collation.
Have you contacted your hosting provider?
Alternatively, you can try changing your collation to utf8_general_ci but that might cause character encoding problems with the existing data.