Redmine

Hello everyone.
I have question about using mysql5.1 with redmine.
I read in page "http://www.redmine.org/wiki/redmine/RedmineInstall" where point to that mysql 5.1+ is not work good with redmine. if more exactly: [[http://www.redmine.org/wiki/redmine/RedmineInstall#Database]] It point to for rails-wramework not work as good work with mysql5.1
but I have work redmine when I start it with mysql5.1.

My question is what is warring in documentation for mysql5.1 and can I get information about what not work in redmine if I use it with mysql5.1

Thanks