IMPORTANT NOTE: if you upgrade to InnoDB-4.1.1 or higher, you cannot downgrade to a version lower than 4.1.1 any more! That is because earlier versions of InnoDB are not aware of multiple tablespaces.
InnoDB in 5.0.0 is essentially the same as InnoDB-4.1.1 with the bug fixes of InnoDB-4.0.17 included.
This is a translation of the MySQL Reference Manual that can be found at dev.mysql.com. The original Reference Manual is in English, and this translation is not necessarily as up to date as the English version.