While updating ownCloud to version 4 it reencoded my already UTF-8-encoded data and left me with borked strings.
I thought about trying to do a bunch of find and replace operations, but I knew this was error prone.
A little internet research produced a very simple simple solution for fixing double-encoded data in MySQL:
mysqldump -u DB_USER -p DB_PASSWORD --opt --quote-names --skip-set-charset --default-character-set=latin1 DB_NAME > DB_NAME-latin1-dump.sql
mysql -u DB_USER -p DB_PASSWORD --default-character-set=utf8 DB_NAME < DB_NAME-latin1-dump.sql
Just replace DB_USER, DB_PASSWORD and DB_NAME with the appropriate values and your good to go. 😀