You have done WordPress website development on a local server and you’re ready to move the WordPress to the live server you go to import your database into your new database and wham you get an MySQL error unknown collation utf8mb4_unicode_ci . What’s going on? Why are you getting this error? It’s probably because your local MySQL is a newer version than the live server is running and the live server does not support utf8mb4_unicode_ci .

The WordPress tables were changed to utf8mb4 with version 4.2 released on 4-23-2015.
utf8mb4 is supported in MySQL version 5.5.3 which dates back to March of 2010.

One work around is when you go to export the local database with phpMyAdmin

Select the database you want to export
Then select Check All
Select Export
Under Export Method:
Select the radio button Custom
Scroll down to Format-specific options: and
Database system or older MySQL server to maximize output compatibility with
and Select MySQL40
Scroll down and Select Go

Save the .sql file and upload into your new database on the live server.

This worked for me on my 1 and 1 hosting linux shared hosting service and the latest
version of WordPress which as of this post is version 4.2.3.

Hope this helps.