Solutions to 4-byte utf-8 characters in mysql 5.1

Question

I'm running into a problem that seems to be an issue w/ mysql 5.1s limitations on UTF8 characters.

From http://dev.mysql.com/doc/refman/5.1/en/charset-unicode-utf8.html

Currently, MySQL support for UTF-8 does not include 4-byte sequences.

Our app is throwing periodic exceptions like

java.sql.SQLException: Incorrect string value: '\xF4\x80\x82\x8C  ...'

The ultimate solution looks to be migrating to 5.5 which supports UTF-8 > 3 bytes

Unfortunately this wouldn't be as simple as bouncing the instances under newer binaries. Being a major version dump we'd need to do a full dump reload which will require some scheduled downtime.

Has anyone else had to deal this situation before? Are there any good work arounds?

The naive approach seems to be have the app search and replace multi-byte sequences with question marks or � . This seems pretty hacky and not a very palatable option to me or the developers.