diff --git a/auth/auth.py b/auth/auth.py
index b8d9065e6..d80915f90 100644
--- a/auth/auth.py
+++ b/auth/auth.py
@@ -22,9 +22,8 @@ from util.http import abort
 
 logger = logging.getLogger(__name__)
 
-
-SIGNATURE_PREFIX = 'signature='
-
+DEPRECATED_SIGNATURE_PREFIX = 'signature'
+SIGNATURE_PREFIX = 'sigv2='
 
 def _load_user_from_cookie():
   if not current_user.is_anonymous():
@@ -196,6 +195,9 @@ def process_auth(func):
     if auth:
       logger.debug('Validating auth header: %s' % auth)
       _process_signed_grant(auth)
+
+      # TODO(jschorr): Remove this once the new version is in prod for a day.
+      _process_token_deprecated(auth)
       _process_basic_auth(auth)
     else:
       logger.debug('No auth header.')
@@ -223,3 +225,46 @@ def extract_namespace_repo_from_session(func):
 
     return func(session['namespace'], session['repository'], *args, **kwargs)
   return wrapper
+
+
+def _process_token_deprecated(auth):
+  normalized = [part.strip() for part in auth.split(' ') if part]
+  if normalized[0].lower() != 'token' or len(normalized) != 2:
+    logger.debug('Not an auth token: %s' % auth)
+    return
+
+  # Skip new tokens.
+  if SIGNATURE_PREFIX in normalized[1]:
+    return
+
+  token_details = normalized[1].split(',')
+
+  if len(token_details) != 1:
+    logger.warning('Invalid token format: %s' % auth)
+    abort(401, message='Invalid token format: %(auth)s', issue='invalid-auth-token', auth=auth)
+
+  def safe_get(lst, index, default_value):
+    try:
+      return lst[index]
+    except IndexError:
+      return default_value
+
+  token_vals = {val[0]: safe_get(val, 1, '') for val in
+                (detail.split('=') for detail in token_details)}
+
+  if DEPRECATED_SIGNATURE_PREFIX not in token_vals:
+    logger.warning('Token does not contain signature: %s' % auth)
+    abort(401, message='Token does not contain a valid signature: %(auth)s',
+          issue='invalid-auth-token', auth=auth)
+
+  try:
+    token_data = model.load_token_data(token_vals[DEPRECATED_SIGNATURE_PREFIX])
+  except model.InvalidTokenException:
+    logger.warning('Token could not be validated: %s', token_vals[DEPRECATED_SIGNATURE_PREFIX])
+    abort(401, message='Token could not be validated: %(auth)s', issue='invalid-auth-token',
+          auth=auth)
+
+  logger.debug('Successfully validated token: %s', token_data.code)
+  set_validated_token(token_data)
+
+  identity_changed.send(app, identity=Identity(token_data.code, 'token'))
\ No newline at end of file