diff --git a/IPython/core/extensions.py b/IPython/core/extensions.py
index ce419e1..21fba40 100644
--- a/IPython/core/extensions.py
+++ b/IPython/core/extensions.py
@@ -88,13 +88,7 @@ class ExtensionManager(Configurable):
 
         with self.shell.builtin_trap:
             if module_str not in sys.modules:
-                with prepended_to_syspath(self.ipython_extension_dir):
-                    mod = import_module(module_str)
-                    if mod.__file__.startswith(self.ipython_extension_dir):
-                        print(("Loading extensions from {dir} is deprecated. "
-                               "We recommend managing extensions like any "
-                               "other Python packages, in site-packages.").format(
-                              dir=compress_user(self.ipython_extension_dir)))
+                mod = import_module(module_str)
             mod = sys.modules[module_str]
             if self._call_load_ipython_extension(mod):
                 self.loaded.add(module_str)
@@ -155,13 +149,3 @@ class ExtensionManager(Configurable):
         if hasattr(mod, 'unload_ipython_extension'):
             mod.unload_ipython_extension(self.shell)
             return True
-
-    @undoc
-    def install_extension(self, url, filename=None):
-        """
-        Deprecated.
-        """
-        # Ensure the extension directory exists
-        raise DeprecationWarning(
-            '`install_extension` and the `install_ext` magic have been deprecated since IPython 4.0'
-            'Use pip or other package managers to manage ipython extensions.')
diff --git a/docs/source/config/extensions/index.rst b/docs/source/config/extensions/index.rst
index e3c9cab..4b0a222 100644
--- a/docs/source/config/extensions/index.rst
+++ b/docs/source/config/extensions/index.rst
@@ -6,8 +6,7 @@ IPython extensions
 
 A level above configuration are IPython extensions, Python modules which modify
 the behaviour of the shell. They are referred to by an importable module name,
-and can be placed anywhere you'd normally import from, or in
-``.ipython/extensions/``.
+and can be placed anywhere you'd normally import from.
 
 Getting extensions
 ==================
@@ -71,10 +70,7 @@ Useful :class:`InteractiveShell` methods include :meth:`~IPython.core.interactiv
    :ref:`defining_magics`
 
 You can put your extension modules anywhere you want, as long as they can be
-imported by Python's standard import mechanism. However, to make it easy to
-write extensions, you can also put your extensions in :file:`extensions/`
-within the :ref:`IPython directory <ipythondir>`. This directory is
-added to :data:`sys.path` automatically.
+imported by Python's standard import mechanism.
 
 When your extension is ready for general use, please add it to the `extensions
 index <https://github.com/ipython/ipython/wiki/Extensions-Index>`_. We also