I'm going to call this superseded just to avoid collision in the key

pep-0001.txt

@@ -271,7 +271,7 @@ optional and are described below.  All other headers are required. ::
     Author: <list of authors' real names and optionally, email addrs>
   * Discussions-To: <email address>
     Status: <Draft | Active | Accepted | Deferred | Rejected |
-             Withdrawn | Final | Replaced>
+             Withdrawn | Final | Superseded>
     Type: <Standards Track | Informational | Process>
   * Content-Type: <text/plain | text/x-rst>
   * Requires: <pep numbers>
@@ -279,7 +279,7 @@ optional and are described below.  All other headers are required. ::
   * Python-Version: <version number>
     Post-History: <dates of postings to python-list and python-dev>
   * Replaces: <pep number>
-  * Replaced-By: <pep number>
+  * Superseded-By: <pep number>
   * Resolution: <url>
 
 The Author header lists the names, and optionally the email addresses
@@ -334,9 +334,9 @@ Informational and Process PEPs do not need a Python-Version header.
 PEPs may have a Requires header, indicating the PEP numbers that this
 PEP depends on.
 
-PEPs may also have a Replaced-By header indicating that a PEP has been
-rendered obsolete by a later document; the value is the number of the
-PEP that replaces the current document.  The newer PEP must have a
+PEPs may also have a Superseded-By header indicating that a PEP has
+been rendered obsolete by a later document; the value is the number of
+the PEP that replaces the current document.  The newer PEP must have a
 Replaces header containing the number of the PEP that it rendered
 obsolete.
 

pep-0102.txt

@@ -5,11 +5,11 @@ Last-Modified: $Date$
 Author: anthony@interlink.com.au (Anthony Baxter), 
     barry@python.org (Barry Warsaw), 
     guido@python.org (Guido van Rossum)
-Status: Replaced
+Status: Superseded
 Type: Informational
 Created: 22-Aug-2001 (edited down on 9-Jan-2002 to become PEP 102)
 Post-History:
-Replaced-By: 101
+Superseded-By: 101
 
 
 Replacement Note

pep-0215.txt

@@ -3,12 +3,12 @@ Title: String Interpolation
 Version: $Revision$
 Last-Modified: $Date$
 Author: ping@zesty.ca (Ka-Ping Yee)
-Status: Rejected
+Status: Superseded
 Type: Standards Track
 Created: 24-Jul-2000
 Python-Version: 2.1
 Post-History:
-Replaced-By: 292
+Superseded-By: 292
 
 Abstract
 

pep-0216.txt

@@ -7,7 +7,7 @@ Status: Rejected
 Type: Informational
 Created: 31-Jul-2000
 Post-History:
-Replaced-By: 287
+Superseded-By: 287
 
 Notice
 

pep-0248.txt

@@ -8,7 +8,7 @@ Status: Final
 Type: Informational
 Created:
 Post-History:
-Replaced-By: 249
+Superseded-By: 249
 
 Introduction
 

pep-0333.txt

@@ -9,7 +9,7 @@ Type: Informational
 Content-Type: text/x-rst
 Created: 07-Dec-2003
 Post-History: 07-Dec-2003, 08-Aug-2004, 20-Aug-2004, 27-Aug-2004, 27-Sep-2010
-Replaced-By: 3333
+Superseded-By: 3333
 
 
 Preface

pep-0344.txt

@@ -3,7 +3,7 @@ Title: Exception Chaining and Embedded Tracebacks
 Version: $Revision$
 Last-Modified: $Date$
 Author: Ka-Ping Yee
-Status: Replaced
+Status: Superseded
 Type: Standards Track
 Content-Type: text/plain
 Created: 12-May-2005

pep-0367.txt

@@ -4,7 +4,7 @@ Version: $Revision$
 Last-Modified: $Date$
 Author: Calvin Spealman <ironfroggy@gmail.com>,
         Tim Delaney <timothy.c.delaney@gmail.com>
-Status: Replaced
+Status: Superseded
 Type: Standards Track
 Content-Type: text/x-rst
 Created: 28-Apr-2007

pep0/output.py

@@ -45,7 +45,7 @@ def sort_peps(peps):
         elif pep.status == 'Draft':
             open_.append(pep)
         elif pep.status in ('Rejected', 'Withdrawn', 'Deferred',
-                'Incomplete', 'Replaced'):
+                'Incomplete', 'Superseeded'):
             dead.append(pep)
         elif pep.type_ == 'Informational':
             # Hack until the conflict between the use of "Final"

pep0/pep.py

@@ -160,14 +160,14 @@ class PEP(object):
                ('Content-Type', False), ('Requires', False),
                ('Created', True), ('Python-Version', False),
                ('Post-History', False), ('Replaces', False),
-               ('Replaced-By', False), ('Resolution', False),
+               ('Superseded-By', False), ('Resolution', False),
                )
     # Valid values for the Type header.
     type_values = (u"Standards Track", u"Informational", u"Process")
     # Valid values for the Status header.
     # Active PEPs can only be for Informational or Process PEPs.
     status_values = (u"Accepted", u"Rejected", u"Withdrawn", u"Deferred",
-                     u"Final", u"Active", u"Draft", u"Replaced")
+                     u"Final", u"Active", u"Draft", u"Superseded")
 
     def __init__(self, pep_file):
         """Init object from an open PEP file object."""