From BlenderWiki

[edit] 2.40 Release

[edit] RIG POSING

[edit] Armature and Rig

 1) Armature is data containing the 'rest position'
 2) Pose is the changes of rest position, and always on object level.
    That way more Objects can use same Pose. Also constraints are in Pose
 3) Actions only contain the Ipos to change values in Poses.

 - Bone selecting in EditMode, selection state is saved for PoseMode,
   and vice-versa
 - Undo in editmode
 - Bone renaming does vertexgroups, constraints, posechannels, actions,
   for all users of Armature in entire file
 - Added Bone renaming in NKey panel
 - Nkey PoseMode shows eulers now
 - EditMode and PoseMode now have 'active' bone too (last clicked)
 - Parenting in EditMode' CTRL+P, ALT+P, with nice options!
 - Pose is added in Outliner now, with showing that constraints are in
   the Pose, not Armature
 
 - PoseMode now is a state Armature Objects can be in. So, while in PoseMode
   for an Armature, you can just select another Object or Armature.
 - The old PoseMode options (transform, insert keys etc) are accessible
   with making the Armature Object 'active' (and have object in PoseMode).
 - At this moment no multiple Poses can be transformed/edited at the same
   time.
 - The old hotkey CTRL+TAB, and view3d header menu, still work to set an
   Object's PoseMode
 

[edit] Armature Posing

 - Added option to the IK buttons, to have it use the 'tip' as end of the
   IK chain. I never really understood this old convention (IK didn't work
   on the Bone itself).
   Old files still will read OK though. But I made the "To Tip" a default
   when adding new IK constraints.
 
 - Hotkey CTRL+I: add IK, with option to have it adding an Empty target,
   or use a selected Bone as target. With the new non-modal PoseMode, it
   gives instant access to playing with the IK chain.
 
 - Hotkey ALT+I: clears IK, on all selected Bones
 
 - Hotkey ALT+C: clears Constraints on all selected Bones (incl IK)

 Added PoseMode CTRL+C copy menu. Does loc/rot/size and constraints.

 Also: for clarity, brought back the display of both Armature Bones as
 Pose Channels. Renaming either works, but you can notice the constraints
 are on Pose, not Armature.
 
 - PoseMode: Shift+S snapmenu: snap cursor to selected now works
 - Outliner: select bones now correctly sets 'active' flag for bones,
   updating the UI as well.
   Also made sure you cannot select hidden bones in outliner.
 - 3DWindow: in PoseMode/EditMode draws name of active Bone too (with user
   option "Draw active object name" set.
 - Added the new Armature/PoseMode options in View3D pulldowns.

 - PoseMode: Wkey menu, "Flip Left/Right Names". On selected bones, it flips
   the L/R tags in names, and calls the proper code to rename everything
   that's related (constraint targets, bone-childs, etc).

 By GuitarGeek
 Added Name flip for
 _L
 _l
 _R
 _r
 
 Also added if suffix == 001, do not re-add suffix. So allows the following procedure
 
  bone named Bone_R is copied, becomes Bone_R.001
 Bone_R.001 is Flipped, becomes Bone_L
 
 Currently only works for 001, could be extended later

 (end GG)

[edit] Posemode and editmode

 - New: Hiding bones in EditMode. This is a separate 'hide flag', so you can
   keep the PoseMode hidden Bones separate from EditMode.

 - While transform(), the hotkeys G,R,S only switch mode when the previous
   mode was compatible. Caused conflicts with Crease/BoneDist/etc.
 - Deleting the last VertexGroup now also deletes the entire Mesh 'dvert'
   data. Sounds logical, but remember that VertexGroups are partial on a
   Mesh, partial on Object. Weird design decision though...
   Anyhoo, at this moment the only way to have Bone Envelopes deform, is
   by deleting all VertexGroups!
 - In PoseMode, the hotkey ALT+S now does both B-Bone size or Envelope,
   depending draw type.
 - In EditMode, Extrude now also works when only Root points were selected.
 - Weight editing is also symmetrical btw, with the "X-axis Mirror" option
   set.

[edit] more More PoseMode

 - In PoseMode, the Constraint Panel now also draws in Editing Buttons, next
   to the Bones Panel.
 - IK Constraint Panel was redesigned... it's still a bit squished
 - Buttons "No X DoF" is now called "Lock X". This to follow convention to
   name options positive.
 - Added Undo push for Make/Clear Parent in Editmode Armature
 - Use CTRL+P "Make Parent" on a single selected Bone to make it become
   connected (ALT+P had already "Disconnect").

[edit] select flipped bone or vertex group

 New: Select/activate flipped bone or vertex group
 - Press SHIFT+F in PoseMode or WeightPaint mode to get the flipped bone.
   Is especially to see while painting if the mirror copying works OK.

 New: "Apply Envelope to VertexGroup" uses X-mirror option too.

[edit] 2.43 Release

[edit] Ghost Path Drawing

[edit] Introduction

The Plumiferos Team have requested some improvements to the ghost and path drawing tools for armatures. These changes make these more useful, with more customisable settings. A new panel in the editing panels for armatures has been added to house these settings.

[edit] Ghosts

In addition to the existing method of showing ghosts either side of the current frame, it is now possible to show ghosts from a given frame range. This is useful for visualising how the poses in another part of the animation changed, while editing another part. The colour of ghosts goes from light (earlier on) to darker (later on).

4 Frames Around Current

In Range 1-23

[edit] Paths

Several new options for path drawing have been added.

• It is now possibly specify a frame range in which to calculate paths too. This offers speedups for longer timelines as a shorter span of time can be sampled.
• It is now possible to specify the distance between highlighted frames.
• Keyframes from the active action/action strip can be shown in a different colour (in the default theme, this is yellow) on the path.
• Frame numbers for the highlighted positions on the path can be drawn.
• You can now choose to have the path of the head ('fat' end) of a bone calculated and shown.

[edit] Notes of Caution

• For ghost range: keep the frame ranges relatively small (20-50 frames), otherwise you will experience a slowdown.
• For path frame numbers: if you have a graphics card which is picky about text in the 3d-view (like x,y,z labels on empty), this may cause issues.
• It is possible that you may experience a slowdown when showing keyframes (especially on larger/longer actions)