diff --git a/rhodecode/controllers/changelog.py b/rhodecode/controllers/changelog.py
--- a/rhodecode/controllers/changelog.py
+++ b/rhodecode/controllers/changelog.py
@@ -22,7 +22,11 @@ Created on April 21, 2010
 changelog controller for pylons
 @author: marcink
 """
-from json import dumps
+try:
+    import json
+except ImportError:
+    #python 2.5 compatibility
+    import simplejson as json
 from mercurial.graphmod import colored, CHANGESET, revisions as graph_rev
 from pylons import request, session, tmpl_context as c
 from rhodecode.lib.auth import LoginRequired, HasRepoPermissionAnyDecorator
@@ -69,7 +73,7 @@ class ChangelogController(BaseController
 
     def _graph(self, repo, size, p):
         revcount = size
-        if not repo.revisions:return dumps([]), 0
+        if not repo.revisions:return json.dumps([]), 0
         
         max_rev = repo.revisions[-1]
         offset = 1 if p == 1 else  ((p - 1) * revcount + 1)
@@ -86,5 +90,5 @@ class ChangelogController(BaseController
                 continue
             data.append(('', vtx, edges))
     
-        c.jsdata = dumps(data) 
+        c.jsdata = json.dumps(data) 
 
diff --git a/rhodecode/controllers/summary.py b/rhodecode/controllers/summary.py
--- a/rhodecode/controllers/summary.py
+++ b/rhodecode/controllers/summary.py
@@ -35,7 +35,11 @@ from datetime import datetime, timedelta
 from time import mktime
 import calendar
 import logging
-import json
+try:
+    import json
+except ImportError:
+    #python 2.5 compatibility
+    import simplejson as json
 log = logging.getLogger(__name__)
 
 class SummaryController(BaseController):