-progress, "Final," which means it is complete and will not change, or
-"Obsolete," which means it should no longer be considered. If a TEP is
-"Obsolete" because it has been replaced by another TEP, then the new
-TEP number should follow "Obsolete," such as "Obsolete by TEP 1231."</p>
+progress, "Final," which means it is complete and will not change.
+Once a TEP has the status "Final," the only change allowed is the
+addition of an "Obsoleted By" field.</p>
+<p>The "Obsoletes" field is a backward pointer to an earlier TEP which
+the current TEP renders obsolete. An Obsoletes field MAY have multiple
+TEPs listed. For example, if TEP 191 were to replace TEPs 111 and 116, it
+would have the field "Obsoletes: 111, 116".</p>
+<p>The "Obsoleted By" field is added to a Final TEP when another TEP has
+rendered it obsolete. The field contains the number of the obsoleting
+TEP. For example, if TEP 111 were obsoleted by TEP 191, it would have
+the field "Obsoleted By: 191".</p>
+<p>"Obsoletes" and "Obsoleted By" fields MUST agree. For a TEP to list another
+TEP in its Obsoletes field, then that TEP MUST list it in the Obsoleted By
+field.</p>
+<p>The obsoletion fields are used to keep track of evolutions and modifications
+of a single abstraction. They are not intended to force a single approach or
+mechanism over alternative possibilities.</p>