libass (0.9.11)
 * Fix serious memory leaks
 * Reduce frame/drawing initialization overhead

libass (0.9.10)
 * Basic (incorrect, but working) support for @font vertical text layout
 * Fix multiple faces per font attachment
 * charmap selection fixes
 * Add ass_flush_events API function
 * Improve fullname font matching
 * Better PAR correction if text transforms are used
 * Calculate drawing bounding box like VSFilter
 * Performance improvements
   * Cache vector clip masks
   * Avoid unnecessary glyph copies
 * Various rendering fixes

libass (0.9.9)
 * Parse numbers in a locale-independent way
 * Remove support for freetype < 2.2.1, fontconfig < 2.4.1; this especially
   means libass will not extract fonts into the file system anymore
 * Disable script file size limit
 * Match fonts against the full name ("name for humans")
 * Reset clip mode after \iclip
 * Improve VSFilter compatibility
 * Update API documentation
 * A couple of smaller fixes and cleanups

libass (0.9.8)
 * Support \q override tag
 * Support wrap style 1 (i.e. wrap, but do not equalize line lengths)
 * Support border style 3 (opaque box)
 * Use the event bounding box (instead of vertical position and height) for
   collision detection
 * Embold glyphs if no bold variant is available, but was requested
 * Modify \fax to be similar to VSFilter
 * Trim spaces after line wrapping
 * Fix border/shadow overlap combining in some cases
 * Disable kerning by default.  Use "Kerning=yes" style override or
   "Kerning: yes" in [Script Info] to enable it
 * Slight bitmap handling optimizations
 * Various bugfixes

libass (0.9.7)
 * Build system fixes
 * Fixed cache lookup and overload problems
 * All globals have been eliminated, libass is reentrant
 * Dynamically allocate glyph and line buffers
 * Fix up stroking of big borders
 * Support empty lines (\N\N)
 * Support for the following override tags:
   \fax, \fay, \xshad, \yshad, \ybord, \xbord, \iclip, \u, \s, \p, \pbo
 * Full subpixel accuracy for positioning
 * PAR and rotation correction for EOSD rendering
 * Drawing mode (including vector \clip and \iclip)
 * Fixed a few memory leaks
 * Removed MPlayer compatibility code
 * Introduced message handling callback
 * Various fixes to match VSFilter quirks and Windows font metrics
 * Lots of bugfixes

LibASS (0.9.6)
 * Various fixes and updates to match VSFilter renderer.
 * Support \blur tag and ScaledBordersAndShadow property.
 * Fractional arguments and subpixel accuracy.
 * Keep positions when pan-and-scan is used.
 * Lots of bugfixes and other changes.

LibASS (0.9.5)
 * Support '=' and '.' in style name in arguments to ass_set_style_overrides().
 * Allow overriding [Script Info] parameters with ass_set_style_overrides().
 * Add workarounds for some buggy fonts.
 * Remove buggy workarounds for some other fonts.
 * Fixed ass_set_line_spacing() (was broken before).
 * Negative margin sizes are now used for image cropping.
 * Better handling of behind-the-camera objects.
 * Case insensitive parsing of SSA/ASS section headers.
 * Improved font matching.
 * When 2 styles have the same name, the later one is used.
 * Fixed several other bugs.