--- a/python/mozboot/mozboot/bootstrap.py
+++ b/python/mozboot/mozboot/bootstrap.py
@@ -412,17 +412,17 @@ def current_firefox_checkout(check_outpu
 
     path = os.getcwd()
     while path:
         hg_dir = os.path.join(path, '.hg')
         git_dir = os.path.join(path, '.git')
         if hg and os.path.exists(hg_dir):
             # Verify the hg repo is a Firefox repo by looking at rev 0.
             try:
-                node = check_output([hg, 'log', '-r', '0', '-T', '{node}'], cwd=path)
+                node = check_output([hg, 'log', '-r', '0', '--template', '{node}'], cwd=path)
                 if node in HG_ROOT_REVISIONS:
                     return 'hg'
                 # Else the root revision is different. There could be nested
                 # repos. So keep traversing the parents.
             except subprocess.CalledProcessError:
                 pass
 
         # TODO check git remotes or `git rev-parse -q --verify $sha1^{commit}`

--- a/python/mozlint/mozlint/vcs.py
+++ b/python/mozlint/mozlint/vcs.py
@@ -44,17 +44,17 @@ class VCSFiles(object):
         return self.vcs == 'git'
 
     def _run(self, cmd):
         files = subprocess.check_output(cmd).split()
         return [os.path.join(self.root, f) for f in files]
 
     def by_rev(self, rev):
         if self.is_hg:
-            return self._run(['hg', 'log', '-T', '{files % "\\n{file}"}', '-r', rev])
+            return self._run(['hg', 'log', '--template', '{files % "\\n{file}"}', '-r', rev])
         elif self.is_git:
             return self._run(['git', 'diff', '--name-only', rev])
         return []
 
     def by_workdir(self):
         if self.is_hg:
             return self._run(['hg', 'status', '-amn'])
         elif self.is_git: