4 byte Unicode characters aren’t yet widely used, so not every application out there fully supports them. MySQL 5.5 works fine with 4 byte characters when properly configured – check if your other components can work with them as well.
Here’s a few other things to check out:
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Make sure all your tables’ default character sets and text fields are converted to utf8mb4, in addition to setting the client & server character sets, e.g.
ALTER TABLE mytable charset=utf8mb4, MODIFY COLUMN textfield1 VARCHAR(255) CHARACTER SET utf8mb4,MODIFY COLUMN textfield2 VARCHAR(255) CHARACTER SET utf8mb4;and so on.If your data is already in the utf8 character set, it should convert to utf8mb4 in place without any problems. As always, back up your data before trying!
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Also make sure your app layer sets its database connections’ character set to utf8mb4. Double-check this is actually happening – if you’re running an older version of your chosen framework’s mysql client library, it may not have been compiled with utf8mb4 support and it won’t set the charset properly. If not, you may have to update it or compile it yourself.
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When viewing your data through the mysql client, make sure you’re on a machine that can display emoji, and run a
SET NAMES utf8mb4before running any queries.
Once every level of your application can support the new characters, you should be able to use them without any corruption.