With the recent update, WordPress changed their encoding standard from utf8 to utf8mb4, which is only supported starting with MYSQL server version 5.5.3 released in 2010.
If you are running a MYSQL server version 5.5.2 or below chances are that you will fail to import the database with error message – Unknown collation: ‘ utf8mb4_unicode_ci ’.
I strongly advise that you update your MYSQL server to version 5.5.3 or higher. If for any reason you are unable to do so, you can export your MYSQL database in a legacy format:
- Open PHPMYADMIN on your local development server.
- Open your WordPress database.
- Go to ‘Export’ and select the ‘Custom’ export method.
- Look for ‘Database system or older MySQL server to maximize output compatibility with:’ and select MYSQL40.
- Export the database as usual.
Now you will be able to import the database on your old MYSQL server. I have tested this on a client’s MYSQL server running at version 5.1.73.