diff --git a/IPython/core/page.py b/IPython/core/page.py
index c39569e..518b6f9 100644
--- a/IPython/core/page.py
+++ b/IPython/core/page.py
@@ -133,7 +133,10 @@ def _detect_screen_size(screen_lines_def):
     #screen_cols,'columns.' # dbg
 
 def page(strng, start=0, screen_lines=0, pager_cmd=None):
-    """Print a string, piping through a pager after a certain length.
+    """Display a string, piping through a pager after a certain length.
+    
+    strng can be a mime-bundle dict, supplying multiple representations,
+    keyed by mime-type.
 
     The screen_lines parameter specifies the number of *usable* lines of your
     terminal screen (total lines minus lines you need to reserve to show other
diff --git a/IPython/core/release.py b/IPython/core/release.py
index 5030263..822b940 100644
--- a/IPython/core/release.py
+++ b/IPython/core/release.py
@@ -40,8 +40,8 @@ version = __version__  # backwards compatibility name
 version_info = (_version_major, _version_minor, _version_patch, _version_extra)
 
 # Change this when incrementing the kernel protocol version
-kernel_protocol_version_info = (5, 0, 0)
-kernel_protocol_version = "%i.%i.%i" % kernel_protocol_version_info
+kernel_protocol_version_info = (5, 0)
+kernel_protocol_version = "%i.%i" % kernel_protocol_version_info
 
 description = "IPython: Productive Interactive Computing"
 
diff --git a/IPython/html/static/notebook/js/tooltip.js b/IPython/html/static/notebook/js/tooltip.js
index 066f709..76d1ec0 100644
--- a/IPython/html/static/notebook/js/tooltip.js
+++ b/IPython/html/static/notebook/js/tooltip.js
@@ -251,11 +251,6 @@ var IPython = (function (IPython) {
             this.reset_tabs_function (cell, text);
         }
 
-        // don't do anything if line begins with '(' or is empty
-        // if (text === "" || text === "(") {
-        //     return;
-        // }
-
         this.tabs_functions[this._consecutive_counter](cell, text, cursor_pos);
 
         // then if we are at the end of list function, reset
diff --git a/IPython/kernel/channels.py b/IPython/kernel/channels.py
index 73511f1..4d875ba 100644
--- a/IPython/kernel/channels.py
+++ b/IPython/kernel/channels.py
@@ -270,7 +270,7 @@ class ShellChannel(ZMQSocketChannel):
         self._queue_send(msg)
         return msg['header']['msg_id']
 
-    def complete(self, code, cursor_pos=0, block=None):
+    def complete(self, code, cursor_pos=None):
         """Tab complete text in the kernel's namespace.
 
         Parameters
@@ -280,17 +280,20 @@ class ShellChannel(ZMQSocketChannel):
             Can be anything between a variable name and an entire cell.
         cursor_pos : int, optional
             The position of the cursor in the block of code where the completion was requested.
+            Default: ``len(code)``
 
         Returns
         -------
         The msg_id of the message sent.
         """
+        if cursor_pos is None:
+            cursor_pos = len(code)
         content = dict(code=code, cursor_pos=cursor_pos)
         msg = self.session.msg('complete_request', content)
         self._queue_send(msg)
         return msg['header']['msg_id']
 
-    def inspect(self, code, cursor_pos=0, detail_level=0):
+    def inspect(self, code, cursor_pos=None, detail_level=0):
         """Get metadata information about an object in the kernel's namespace.
 
         It is up to the kernel to determine the appropriate object to inspect.
@@ -302,6 +305,7 @@ class ShellChannel(ZMQSocketChannel):
             Can be anything between a variable name and an entire cell.
         cursor_pos : int, optional
             The position of the cursor in the block of code where the info was requested.
+            Default: ``len(code)``
         detail_level : int, optional
             The level of detail for the introspection (0-2)
 
@@ -309,6 +313,8 @@ class ShellChannel(ZMQSocketChannel):
         -------
         The msg_id of the message sent.
         """
+        if cursor_pos is None:
+            cursor_pos = len(code)
         content = dict(code=code, cursor_pos=cursor_pos,
             detail_level=detail_level,
         )
diff --git a/IPython/kernel/inprocess/channels.py b/IPython/kernel/inprocess/channels.py
index 8a7459b..25eb1a0 100644
--- a/IPython/kernel/inprocess/channels.py
+++ b/IPython/kernel/inprocess/channels.py
@@ -94,13 +94,17 @@ class InProcessShellChannel(InProcessChannel):
         self._dispatch_to_kernel(msg)
         return msg['header']['msg_id']
 
-    def complete(self, code, cursor_pos=0):
+    def complete(self, code, cursor_pos=None):
+        if cursor_pos is None:
+            cursor_pos = len(code)
         content = dict(code=code, cursor_pos=cursor_pos)
         msg = self.client.session.msg('complete_request', content)
         self._dispatch_to_kernel(msg)
         return msg['header']['msg_id']
 
-    def inspect(self, code, cursor_pos=0, detail_level=0):
+    def inspect(self, code, cursor_pos=None, detail_level=0):
+        if cursor_pos is None:
+            cursor_pos = len(code)
         content = dict(code=code, cursor_pos=cursor_pos,
             detail_level=detail_level,
         )
diff --git a/IPython/kernel/tests/test_message_spec.py b/IPython/kernel/tests/test_message_spec.py
index 0850a1d..e1080e9 100644
--- a/IPython/kernel/tests/test_message_spec.py
+++ b/IPython/kernel/tests/test_message_spec.py
@@ -59,11 +59,20 @@ class Reference(HasTraits):
             except TraitError as e:
                 assert False, str(e)
 
+
 class Version(Unicode):
+    def __init__(self, *args, **kwargs):
+        self.min = kwargs.pop('min', None)
+        self.max = kwargs.pop('max', None)
+        kwargs['default_value'] = self.min
+        super(Version, self).__init__(*args, **kwargs)
+    
     def validate(self, obj, value):
-        min_version = self.default_value
-        if V(value) < V(min_version):
-            raise TraitError("bad version: %s < %s" % (value, min_version))
+        if self.min and V(value) < V(self.min):
+            raise TraitError("bad version: %s < %s" % (value, self.min))
+        if self.max and (V(value) > V(self.max)):
+            raise TraitError("bad version: %s > %s" % (value, self.max))
+
 
 class RMessage(Reference):
     msg_id = Unicode()
@@ -83,9 +92,9 @@ class RHeader(Reference):
     msg_type = Unicode()
     session = Unicode()
     username = Unicode()
-    version = Version('5.0')
+    version = Version(min='5.0')
 
-mime_pat = re.compile(r'\w+/\w+')
+mime_pat = re.compile(r'^[\w\-\+\.]+/[\w\-\+\.]+$')
 
 class MimeBundle(Reference):
     metadata = Dict()
@@ -143,10 +152,10 @@ class CompleteReply(Reference):
 
 
 class KernelInfoReply(Reference):
-    protocol_version = Version('5.0')
+    protocol_version = Version(min='5.0')
     implementation = Unicode('ipython')
-    implementation_version = Version('2.1')
-    language_version = Version('2.7')
+    implementation_version = Version(min='2.1')
+    language_version = Version(min='2.7')
     language = Unicode('python')
     banner = Unicode()
 
diff --git a/IPython/kernel/zmq/ipkernel.py b/IPython/kernel/zmq/ipkernel.py
index 6e23029..09ce934 100755
--- a/IPython/kernel/zmq/ipkernel.py
+++ b/IPython/kernel/zmq/ipkernel.py
@@ -369,9 +369,13 @@ class Kernel(Configurable):
         getpass.getpass = self._save_getpass
     
     def set_parent(self, ident, parent):
-        """Record the parent state
+        """Set the current parent_header
         
-        For associating side effects with their requests.
+        Side effects (IOPub messages) and replies are associated with
+        the request that caused them via the parent_header.
+        
+        The parent identity is used to route input_request messages
+        on the stdin channel.
         """
         self._parent_ident = ident
         self._parent_header = parent
@@ -617,9 +621,6 @@ class Kernel(Configurable):
         shell = self.shell
         shell.set_parent(parent)
 
-        # execute_input_msg = self.session.msg(u'execute_input',{u'code':code}, parent=parent)
-        # self.iopub_socket.send(execute_input_msg)
-        # self.session.send(self.iopub_socket, u'execute_input', {u'code':code},parent=parent)
         md = self._make_metadata(parent['metadata'])
         try:
             working = shell.user_ns
diff --git a/IPython/qt/console/frontend_widget.py b/IPython/qt/console/frontend_widget.py
index 00de669..62d7332 100644
--- a/IPython/qt/console/frontend_widget.py
+++ b/IPython/qt/console/frontend_widget.py
@@ -512,10 +512,6 @@ class FrontendWidget(HistoryConsoleWidget, BaseFrontendMixin):
         info = self._request_info.get('call_tip')
         if info and info.id == rep['parent_header']['msg_id'] and \
                 info.pos == cursor.position():
-            # Get the information for a call tip.  For now we format the call
-            # line as string, later we can pass False to format_call and
-            # syntax-highlight it ourselves for nicer formatting in the
-            # calltip.
             content = rep['content']
             if content.get('status') == 'ok':
                 self._call_tip_widget.show_inspect_data(content)
diff --git a/docs/source/development/execution.rst b/docs/source/development/execution.rst
index 8aa2a4a..8350c04 100644
--- a/docs/source/development/execution.rst
+++ b/docs/source/development/execution.rst
@@ -10,14 +10,12 @@ The execution of use code consists of the following phases:
 3. Execute the ``code`` field, see below for details.
 4. If execution succeeds, expressions in ``user_expressions`` are computed.
    This ensures that any error in the expressions don't affect the main code execution.
-5. Fire the post_execute eventCall any method registered with :meth:`register_post_execute`.
+5. Fire the post_execute event.
 
-.. warning::
+.. seealso::
+
+    :doc:`config/callbacks`
 
-   The API for running code before/after the main code block is likely to
-   change soon.  Both the ``pre_runcode_hook`` and the
-   :meth:`register_post_execute` are susceptible to modification, as we find a
-   consistent model for both.
 
 To understand how the ``code`` field is executed, one must know that Python
 code can be compiled in one of three modes (controlled by the ``mode`` argument
@@ -64,7 +62,3 @@ execution in 'single' mode, and then:
     unit.
 
 
-Errors in any registered post_execute functions are reported,
-and the failing function is removed from the post_execution set so that it does
-not continue triggering failures.
-
diff --git a/docs/source/development/messaging.rst b/docs/source/development/messaging.rst
index 42764e1..6c145c4 100644
--- a/docs/source/development/messaging.rst
+++ b/docs/source/development/messaging.rst
@@ -9,7 +9,7 @@ Versioning
 ==========
 
 The IPython message specification is versioned independently of IPython.
-The current version of the specification is 5.0.0.
+The current version of the specification is 5.0.
 
 
 Introduction
@@ -107,7 +107,7 @@ A message is defined by the following four-dictionary structure::
                     # All recognized message type strings are listed below.
                     'msg_type' : str,
                     # the message protocol version
-                    'version' : '5.0.0',
+                    'version' : '5.0',
          },
 
       # In a chain of messages, the header from the parent is copied so that
@@ -122,7 +122,7 @@ A message is defined by the following four-dictionary structure::
       'content' : dict,
     }
 
-.. versionchanged:: 5.0.0
+.. versionchanged:: 5.0
 
     ``version`` key added to the header.
 
@@ -281,7 +281,7 @@ Message type: ``execute_request``::
     'allow_stdin' : True,
     }
 
-.. versionchanged:: 5.0.0
+.. versionchanged:: 5.0
 
     ``user_variables`` removed, because it is redundant with user_expressions.
 
@@ -366,7 +366,7 @@ When status is 'ok', the following extra fields are present::
       'user_expressions' : dict,
     }
 
-.. versionchanged:: 5.0.0
+.. versionchanged:: 5.0
 
     ``user_variables`` is removed, use user_expressions instead.
 
@@ -433,11 +433,11 @@ Message type: ``inspect_request``::
         'detail_level' : 0 or 1,
     }
 
-.. versionchanged:: 5.0.0
+.. versionchanged:: 5.0
 
     ``object_info_request`` renamed to ``inspect_request``.
 
-.. versionchanged:: 5.0.0
+.. versionchanged:: 5.0
 
     ``name`` key replaced with ``code`` and ``cursor_pos``,
     moving the lexing responsibility to the kernel.
@@ -457,11 +457,11 @@ Message type: ``inspect_reply``::
         'metadata' : dict,
     }
 
-.. versionchanged:: 5.0.0
+.. versionchanged:: 5.0
 
     ``object_info_reply`` renamed to ``inspect_reply``.
 
-.. versionchanged:: 5.0.0
+.. versionchanged:: 5.0
 
     Reply is changed from structured data to a mime bundle,  allowing formatting decisions to be made by the kernel.
 
@@ -480,7 +480,7 @@ Message type: ``complete_request``::
         'cursor_pos' : int,
     }
 
-.. versionchanged:: 5.0.0
+.. versionchanged:: 5.0
 
     ``line``, ``block``, and ``text`` keys are removed in favor of a single ``code`` for context.
     Lexing is up to the kernel.
@@ -507,7 +507,7 @@ Message type: ``complete_reply``::
     'status' : 'ok'
     }
 
-.. versionchanged:: 5.0.0
+.. versionchanged:: 5.0
 
     - ``matched_text`` is removed in favor of ``cursor_start`` and ``cursor_end``.
     - ``metadata`` is added for extended information.
@@ -638,15 +638,15 @@ Message type: ``kernel_info_reply``::
         'banner' : str,
     }
 
-.. versionchanged:: 5.0.0
+.. versionchanged:: 5.0
 
     Versions changed from lists of integers to strings.
     
-.. versionchanged:: 5.0.0
+.. versionchanged:: 5.0
 
     ``ipython_version`` is removed.
 
-.. versionchanged:: 5.0.0
+.. versionchanged:: 5.0
 
     ``implementation``, ``implementation_version``, and ``banner`` keys are added.
 
@@ -760,7 +760,7 @@ of images::
     }
 
 
-.. versionchanged:: 5.0.0
+.. versionchanged:: 5.0
 
     `application/json` data should be unpacked JSON data,
     not double-serialized as a JSON string.
@@ -822,7 +822,7 @@ Message type: ``execute_input``::
         'execution_count' : int
     }
 
-.. versionchanged:: 5.0.0
+.. versionchanged:: 5.0
 
     ``pyin`` is renamed to ``execute_input``.
 
@@ -868,7 +868,7 @@ Message type: ``error``::
        # except the 'status' field is omitted.
     }
 
-.. versionchanged:: 5.0.0
+.. versionchanged:: 5.0
 
     ``pyerr`` renamed to ``error``
 
@@ -937,7 +937,7 @@ Message type: ``input_reply``::
 
 When ``password`` is True, the frontend should not echo the input as it is entered.
 
-.. versionchanged:: 5.0.0
+.. versionchanged:: 5.0
 
     ``password`` key added.