The version number distinguishes different editions of a HYPeR module. The version number is a three didgit number divided by ``.'' like this x.y.z and is printed on the cover of the module. An edition of a module m is newer than module m', if the version number is higher. A higher number in the ``z'' part means only a change of some type-set errors of the previous version. A higher y number, which also resets the ``z'' part, means that there are some changes in one or more chapters and/or the addition of a chapter/part. A change of the first number ``x'' means really big changes, maybe some rules become obsolete. Always refer to the file CHANGES which records all the changes that are made since all previous versions.