diff --git a/Doc/tools/dailybuild.py b/Doc/tools/dailybuild.py
index 2cc3d8c..786d5ab 100755
--- a/Doc/tools/dailybuild.py
+++ b/Doc/tools/dailybuild.py
@@ -34,12 +34,29 @@
 
 BRANCHES = [
     # checkout, target, isdev
-    (BUILDROOT + '/python33', WWWROOT + '/3.3', False),
-    (BUILDROOT + '/python34', WWWROOT + '/3.4', True),
+    (BUILDROOT + '/python34', WWWROOT + '/3.4', False),
+    (BUILDROOT + '/python35', WWWROOT + '/3.5', True),
     (BUILDROOT + '/python27', WWWROOT + '/2.7', False),
 ]
 
 
+def _files_changed(old, new):
+    with open(old, 'rb') as fp1, open(new, 'rb') as fp2:
+        st1 = os.fstat(fp1.fileno())
+        st2 = os.fstat(fp2.fileno())
+        if st1.st_size != st2.st_size:
+            return False
+        if st1.st_mtime >= st2.st_mtime:
+            return True
+        while True:
+            one = fp1.read(4096)
+            two = fp2.read(4096)
+            if one != two:
+                return False
+            if one == '':
+                break
+    return True
+
 def build_one(checkout, target, isdev, quick):
     print 'Doc autobuild started in %s' % checkout
     os.chdir(checkout)
@@ -51,12 +68,40 @@
     if os.WEXITSTATUS(os.system('cd Doc; make SPHINXBUILD=%s %s' % (SPHINXBUILD, maketarget))) == 2:
         print '*' * 80
         return
+    print('Computing changed files')
+    changed = []
+    for dirpath, dirnames, filenames in os.walk('Doc/build/html/'):
+        dir_rel = dirpath[len('Doc/build/html/'):]
+        for fn in filenames:
+            local_path = os.path.join(dirpath, fn)
+            rel_path = os.path.join(dir_rel, fn)
+            target_path = os.path.join(target, rel_path)
+            if (os.path.exists(target_path) and
+                not _files_changed(target_path, local_path)):
+                changed.append(rel_path)
     print 'Copying HTML files to %s' % target
     os.system('cp -a Doc/build/html/* %s' % target)
     if not quick:
         print 'Copying dist files'
         os.system('mkdir -p %s/archives' % target)
         os.system('cp -a Doc/dist/* %s/archives' % target)
+        changed.append('archives/')
+        for fn in os.listdir(os.path.join(target, 'archives')):
+            changed.append('archives/' + fn)
+    print '%s files changed' % len(changed)
+    if changed:
+        target_ino = os.stat(target).st_ino
+        targets_dir = os.path.dirname(target)
+        prefixes = []
+        for fn in os.listdir(targets_dir):
+            if os.stat(os.path.join(targets_dir, fn)).st_ino == target_ino:
+                prefixes.append(fn)
+        to_purge = []
+        for prefix in prefixes:
+            to_purge.extend(prefix + "/" + p for p in changed)
+        purge_cmd = 'curl -X PURGE "https://docs.python.org/{%s}"' % ','.join(to_purge)
+        print("Running CDN purge")
+        os.system(purge_cmd)
     print 'Finished'
     print '=' * 80
 
@@ -84,7 +129,7 @@
     if args:
         if len(args) != 2:
             usage()
-        build_one(args[0], args[1], devel, quick)
+        build_one(os.path.abspath(args[0]), os.path.abspath(args[1]), devel, quick)
     else:
         for checkout, dest, devel in BRANCHES:
             build_one(checkout, dest, devel, quick)