This patches allow you to select sorting order method of the discussion topics. In current version of Moodle1.8 the list of discussion topics is displayed in order of 'Last Post' only. We can not follow the relationship a topic and next topic.
After applying these three paches we can select three sorting methods of discussion topics. One is origginal sorting method (Last Post), and the others are sorting by 'First Post (From older)' and 'First Post (From newer)' according to date of discussion topic.