diff --git a/doc/config.rst b/doc/config.rst
index 4b74a2129..79c08081a 100644
--- a/doc/config.rst
+++ b/doc/config.rst
@@ -1617,6 +1617,10 @@ These options influence LaTeX output. See further :doc:`latex`.
 
    .. versionadded:: 1.4.5
 
+   .. versionchanged:: 1.6
+
+      For ``'xelatex'`` engine, the default is ``False`` because LaTeX package
+      ``fontspec v2.6`` defines its own ``\strong`` macro.
 
 .. confval:: latex_elements
 
diff --git a/sphinx/builders/latex.py b/sphinx/builders/latex.py
index 493da2ccb..346bd510e 100644
--- a/sphinx/builders/latex.py
+++ b/sphinx/builders/latex.py
@@ -258,6 +258,11 @@ def validate_config_values(app):
                           RemovedInSphinx17Warning)
             app.config.latex_elements['postamble'] = app.config.latex_elements['footer']
 
+    if app.config.latex_keep_old_macro_names:
+        warnings.warn("latex_keep_old_macro_names is deprecated. "
+                      "LaTeX markup since Sphinx 1.4.5 uses only prefixed macro names.",
+                      RemovedInSphinx17Warning)
+
 
 def default_latex_engine(config):
     # type: (Config) -> unicode
@@ -291,7 +296,7 @@ def setup(app):
                          None)
     app.add_config_value('latex_logo', None, None, string_classes)
     app.add_config_value('latex_appendices', [], None)
-    app.add_config_value('latex_keep_old_macro_names', True, None)
+    app.add_config_value('latex_keep_old_macro_names', False, None)
     app.add_config_value('latex_toplevel_sectioning', None, None, [str])
     app.add_config_value('latex_domain_indices', True, None, [list])
     app.add_config_value('latex_show_urls', 'no', None)
diff --git a/sphinx/texinputs/sphinx.sty b/sphinx/texinputs/sphinx.sty
index 8f17cf5aa..514a455c1 100644
--- a/sphinx/texinputs/sphinx.sty
+++ b/sphinx/texinputs/sphinx.sty
@@ -1199,7 +1199,7 @@
 \ifspx@opt@dontkeepoldnames\else
   \let\spx@alreadydefinedlist\@empty
   \typeout{** (sphinx) defining (legacy) text style macros without \string\sphinx\space prefix}
-  \typeout{** if clashes with packages, set latex_keep_old_macro_names=False
+  \typeout{** if clashes with packages, do not set latex_keep_old_macro_names=True
     in conf.py}
   \@for\@tempa:=code,strong,bfcode,email,tablecontinued,titleref,%
                 menuselection,accelerator,crossref,termref,optional\do
@@ -1224,6 +1224,7 @@
          Sphinx mark-up uses only \string\sphinx\expandafter\@gobble\sphinxdeprecatedmacro.}%
     }%
   \fi
+  \sphinxdeprecationwarning{latex_keep_old_macro_names=True}{1.6}{1.7}{}%
 \fi
 
 % additional customizable styling
diff --git a/sphinx/writers/latex.py b/sphinx/writers/latex.py
index 9d919713d..3699fdc15 100644
--- a/sphinx/writers/latex.py
+++ b/sphinx/writers/latex.py
@@ -58,7 +58,7 @@ DEFAULT_SETTINGS = {
     'classoptions':    '',
     'extraclassoptions': '',
     'maxlistdepth':    '',
-    'sphinxpkgoptions':     '',
+    'sphinxpkgoptions':     'dontkeepoldnames',
     'sphinxsetup':     '',
     'passoptionstopackages': '',
     'geometry':        '\\usepackage{geometry}',
@@ -539,8 +539,8 @@ class LaTeXTranslator(nodes.NodeVisitor):
             self.elements.update({
                 'releasename':  _('Release'),
             })
-        if not builder.config.latex_keep_old_macro_names:
-            self.elements['sphinxpkgoptions'] = 'dontkeepoldnames'
+        if builder.config.latex_keep_old_macro_names:
+            self.elements['sphinxpkgoptions'] = ''
         if document.settings.docclass == 'howto':
             docclass = builder.config.latex_docclass.get('howto', 'article')
         else: