Here are the 0.98.4 notes from the CHANGELOG:

Added mdehoon's native macosx backend from sf patch 2179017 - JDH Removed the prints in the set_*style commands. Return the list of pretty-printed strings instead - JDH Some of the changes Michael made to improve the output of the property tables in the rest docs broke of made difficult to use some of the interactive doc helpers, eg setp and getp. Having all the rest markup in the ipython shell also confused the docstrings. I added a new rc param docstring.harcopy, to format the docstrings differently for hardcopy and other use. The ArtistInspector could use a little refactoring now since there is duplication of effort between the rest out put and the non-rest output - JDH Updated spectral methods (psd, csd, etc.) to scale one-sided densities by a factor of 2 and, optionally, scale all densities by the sampling frequency. This gives better MATLAB compatibility. -RM Fixed alignment of ticks in colorbars. -MGD drop the deprecated "new" keyword of np.histogram() for numpy 1.2 or later. -JJL Fixed a bug in svg backend that new_figure_manager() ignores keywords arguments such as figsize, etc. -JJL Fixed a bug that the handlelength of the new legend class set too short when numpoints=1 -JJL Added support for data with units (e.g., dates) to Axes.fill_between. -RM Added fancybox keyword to legend. Also applied some changes for better look, including baseline adjustment of the multiline texts so that it is center aligned. -JJL The transmuter classes in the patches.py are reorganized as subclasses of the Style classes. A few more box and arrow styles are added. -JJL Fixed a bug in the new legend class that didn't allowed a tuple of coordinate values as loc. -JJL Improve checks for external dependencies, using subprocess (instead of deprecated popen*) and distutils (for version checking) - DSD Reimplementation of the legend which supports baseline alignment, multi-column, and expand mode. - JJL Fixed histogram autoscaling bug when bins or range are given explicitly (fixes Debian bug 503148) - MM Added rcParam axes.unicode_minus which allows plain hyphen for minus when False - JDH Added scatterpoints support in Legend. patch by Erik Tollerud - JJL Fix crash in log ticking. - MGD Added static helper method BrokenHBarCollection.span_where and Axes/pyplot method fill_between. See examples/pylab/fill_between.py - JDH Add x_isdata and y_isdata attributes to Artist instances, and use them to determine whether either or both coordinates are used when updating dataLim. This is used to fix autoscaling problems that had been triggered by axhline, axhspan, axvline, axvspan. - EF Update the psd(), csd(), cohere(), and specgram() methods of Axes and the csd() cohere(), and specgram() functions in mlab to be in sync with the changes to psd(). In fact, under the hood, these all call the same core to do computations. - RM Add 'pad_to' and 'sides' parameters to mlab.psd() to allow controlling of zero padding and returning of negative frequency components, respectively. These are added in a way that does not change the API. - RM Fix handling of c kwarg by scatter; generalize is_string_like to accept numpy and numpy.ma string array scalars. - RM and EF Fix a possible EINTR problem in dviread, which might help when saving pdf files from the qt backend. - JKS Fix bug with zoom to rectangle and twin axes - MGD Added Jae Joon's fancy arrow, box and annotation enhancements -- see examples/pylab_examples/annotation_demo2.py Autoscaling is now supported with shared axes - EF Fixed exception in dviread that happened with Minion - JKS set_xlim, ylim now return a copy of the viewlim array to avoid modify inplace surprises Added image thumbnail generating function matplotlib.image.thumbnail. See examples/misc/image_thumbnail.py - JDH Applied scatleg patch based on ideas and work by Erik Tollerud and Jae-Joon Lee. - MM Fixed bug in pdf backend: if you pass a file object for output instead of a filename, e.g., in a wep app, we now flush the object at the end. - JKS Add path simplification support to paths with gaps. - EF Fix problem with AFM files that don't specify the font's full name or family name. - JKS Added 'scilimits' kwarg to Axes.ticklabel_format() method, for easy access to the set_powerlimits method of the major ScalarFormatter. - EF Experimental new kwarg borderpad to replace pad in legend, based on suggestion by Jae-Joon Lee. - EF Allow spy to ignore zero values in sparse arrays, based on patch by Tony Yu. Also fixed plot to handle empty data arrays, and fixed handling of markers in figlegend. - EF Introduce drawstyles for lines. Transparently split linestyles like 'steps--' into drawstyle 'steps' and linestyle '--'. Legends always use drawstyle 'default'. - MM Fixed quiver and quiverkey bugs (failure to scale properly when resizing) and added additional methods for determining the arrow angles - EF Fix polar interpolation to handle negative values of theta - MGD Reorganized cbook and mlab methods related to numerical calculations that have little to do with the goals of those two modules into a separate module numerical_methods.py Also, added ability to select points and stop point selection with keyboard in ginput and manual contour labeling code. Finally, fixed contour labeling bug. - DMK Fix backtick in Postscript output. - MGD [ 2089958 ] Path simplification for vector output backends Leverage the simplification code exposed through path_to_polygons to simplify certain well-behaved paths in the vector backends (PDF, PS and SVG). "path.simplify" must be set to True in matplotlibrc for this to work. - MGD Add "filled" kwarg to Path.intersects_path and Path.intersects_bbox. - MGD Changed full arrows slightly to avoid an xpdf rendering problem reported by Friedrich Hagedorn. - JKS Fix conversion of quadratic to cubic Bezier curves in PDF and PS backends. Patch by Jae-Joon Lee. - JKS Added 5-point star marker to plot command q- EF Fix hatching in PS backend - MGD Fix log with base 2 - MGD Added support for bilinear interpolation in NonUniformImage; patch by Gregory Lielens. - EF Added support for multiple histograms with data of different length - MM Fix step plots with log scale - MGD Fix masked arrays with markers in non-Agg backends - MGD Fix clip_on kwarg so it actually works correctly - MGD Fix locale problems in SVG backend - MGD fix quiver so masked values are not plotted - JSW improve interactive pan/zoom in qt4 backend on windows - DSD Fix more bugs in NaN/inf handling. In particular, path simplification (which does not handle NaNs or infs) will be turned off automatically when infs or NaNs are present. Also masked arrays are now converted to arrays with NaNs for consistent handling of masks and NaNs - MGD and EF Added support for arbitrary rasterization resolutions to the SVG backend. - MW