Database Errors after 1and1 upgrade to PHP 5.4

I switched my global PHP version to 5.4 and then had problems with various software including WordPress, and Concrete connecting to my mysql database. I found that just going into database administration (after switching the PHP version to 5.4) and updating the mysql password (to the same as before) caused it to use the new hashing mechanism/library… and now the database connections work correctly.