Note that the IRS does not revise every form every year. All major forms are revised annually, but the ones that are less frequently used, and which are not impacted by yearly tax law changes, are revised only when necessary.
Forms revised annually will have the year shown in the upper right hand corner of the form, and forms revised periodically will have their revision date shown underneath the form number in the upper left hand corner of the form.
Each listing below shows the name of the file, its file size, and its official revision date. Most all files in this section are updated yearly, and will have 2001 as the most recent revision.