Format major and minor versions in SharePoint. Keeping previous versions of a document while modifying it makes it easy to step back from recent changes and move forward from there.
To set a Document Library to create major (1, 2, 3) or minor (1.1, 1.2, 1.3) versions, choose the Library, and then in Library tab, Settings group (SharePoint 2010), choose the Library Settings button. Choose the second option under the General Settings category, called Versioning Settings. You can choose the versioning option and the access control associated with drafts, as well as set the requirement for documents to always be checked out.