For detailed information about the changes below, please see the git log or
visit: http://log.libusb.info

2016-07-20: v1.0.21:
* Core: Refactor code related to transfer flags and timeout handling
* Darwin: Ignore root hub simulation devices
* Darwin: Improved support for OS X El Capitan
* Linux: Support preallocating kernel memory for zerocopy USB
* Linux: Deal with receiving POLLERR before all transfers have completed
* Solaris: Add solaris backend
* Windows: Add Visual Studio 2015 support
* Prevent attempts to recursively handle events
* Fix race condition in handle_timeout()
* Allow transferred argument to be optional in bulk APIs
* Various other bug fixes and improvements

2015-09-13: v1.0.20
* Add Haiku support
* Fix multiple memory and resource leaks (#16, #52, #76, #81)
* Fix possible deadlock when executing transfer callback
* New libusb_free_pollfds() API
* Darwin: Fix devices not being detected on OS X 10.8 (#48)
* Linux: Allow larger isochronous transfer submission (#23)
* Windows: Fix broken builds Cygwin/MinGW builds and compiler warnings
* Windows: Fix broken bus number lookup
* Windows: Improve submission of control requests for composite devices
* Examples: Add two-stage load support to fxload (#12)
* Correctly report cancellations due to timeouts
* Improve efficiency of event handling
* Improve speed of transfer submission in multi-threaded environments
* Various other bug fixes and improvements
The (#xx) numbers are libusb issue numbers, see ie:
https://github.com/libusb/libusb/issues/16

2014-05-30: v1.0.19
* Add support for USB bulk streams on Linux and Mac OS X (#11)
* Windows: Add AMD and Intel USB-3.0 root hub support
* Windows: Fix USB 3.0 speed detection on Windows 8 or later (#10)
* Added Russian translation for libusb_strerror strings
* All: Various small fixes and cleanups

2014-01-25: v1.0.18
* Fix multiple memory leaks
* Fix a crash when HID transfers return no data on Windows
* Ensure all pending events are consumed
* Improve Android and ucLinux support
* Multiple Windows improvements (error logging, VS2013, VIA xHCI support)
* Multiple OS X improvements (broken compilation, SIGFPE, 64bit support)

2013-09-06: v1.0.17
* Hotplug callbacks now always get passed a libusb_context, even if it is
  the default context. Previously NULL would be passed for the default context,
  but since the first context created is the default context, and most apps
  use only 1 context, this meant that apps explicitly creating a context would
  still get passed NULL
* Android: Add .mk files to build with the Android NDK
* Darwin: Add Xcode project
* Darwin: Fix crash on unplug (#121)
* Linux: Fix hang (deadlock) on libusb_exit
* Linux: Fix libusb build failure with --disable-udev (#124)
* Linux: Fix libusb_get_device_list() hang with --disable-udev (#130)
* OpenBSD: Update OpenBSD backend with support for control transfers to
  non-ugen(4) devices and make get_configuration() no longer generate I/O.
  Note that using this libusb version on OpenBSD requires using
  OpenBSD 5.3-current or later. Users of older OpenBSD versions are advised
  to stay with the libusb shipped with OpenBSD (mpi)
* Windows: fix libusb_dll_2010.vcxproj link errors (#129)
* Various other bug fixes and improvements

2013-07-11: v1.0.16
* Add hotplug support for Darwin and Linux (#9)
* Add superspeed endpoint companion descriptor support (#15)
* Add BOS descriptor support (#15)
* Make descriptor parsing code more robust
* New libusb_get_port_numbers API, this is libusb_get_port_path without
  the unnecessary context parameter, libusb_get_port_path is now deprecated
* New libusb_strerror API (#14)
* New libusb_set_auto_detach_kernel_driver API (#17)
* Improve topology API docs (#95)
* Logging now use a single write call per log-message, avoiding log-message
  "interlacing" when using multiple threads.
* Android: use Android logging when building on Android (#101)
* Darwin: make libusb_reset reenumerate device on descriptors change (#89)
* Darwin: add support for the LIBUSB_TRANSFER_ADD_ZERO_PACKET flag (#91)
* Darwin: add a device cache (#112, #114)
* Examples: Add sam3u_benchmark isochronous example by Harald Welte (#109)
* Many other bug fixes and improvements
The (#xx) numbers are libusbx issue numbers, see ie:
https://github.com/libusbx/libusbx/issues/9

2013-04-15: v1.0.15
* Improve transfer cancellation and avoid short read failures on broken descriptors
* Filter out 8-bit characters in libusb_get_string_descriptor_ascii()
* Add WinCE support
* Add library stress tests
* Add Cypress FX3 firmware upload support for fxload sample
* Add HID and kernel driver detach support capabilities detection
* Add SuperSpeed detection on OS X
* Fix bInterval value interpretation on OS X
* Fix issues with autoclaim, composite HID devices, interface autoclaim and
  early abort in libusb_close() on Windows. Also add VS2012 solution files.
* Improve fd event handling on Linux
* Other bug fixes and improvements

2012-09-26: v1.0.14
* Reverts the previous API change with regards to bMaxPower.
  If this doesn't matter to you, you are encouraged to keep using v1.0.13,
  as it will use the same attribute as v2.0, to be released soon.
* Note that LIBUSB_API_VERSION is *decreased* to 0x010000FF and the previous
  guidelines with regards to concurrent use of MaxPower/bMaxPower still apply.

2012-09-20: v1.0.13
* [MAJOR] Fix a typo in the API with struct libusb_config_descriptor where
  MaxPower was used instead of bMaxPower, as defined in the specs. If your 
  application was accessing the MaxPower attribute, and you need to maintain
  compatibility with libusb or older versions, see APPENDIX A below.
* Fix broken support for the 0.1 -> 1.0 libusb-compat layer
* Fix unwanted cancellation of pending timeouts as well as major timeout related bugs
* Fix handling of HID and composite devices on Windows
* Introduce LIBUSB_API_VERSION macro
* Add Cypress FX/FX2 firmware upload sample, based on fxload from
  http://linux-hotplug.sourceforge.net
* Add libusb0 (libusb-win32) and libusbK driver support on Windows. Note that while
  the drivers allow it, isochronous transfers are not supported yet in libusb. Also
  not supported yet is the use of libusb-win32 filter drivers on composite interfaces
* Add support for the new get_capabilities ioctl on Linux and avoid unnecessary
  splitting of bulk transfers
* Improve support for newer Intel and Renesas USB 3.0 controllers on Windows
* Harmonize the device number for root hubs across platforms
* Other bug fixes and improvements

2012-06-15: v1.0.12
* Fix a potential major regression with pthread on Linux
* Fix missing thread ID from debug log output on cygwin
* Fix possible crash when using longjmp and MinGW's gcc 4.6
* Add topology calls: libusb_get_port_number(), libusb_get_parent() & libusb_get_port_path()
* Add toggleable debug, using libusb_set_debug() or the LIBUSB_DEBUG environment variable
* Define log levels in libusb.h and set timestamp origin to first libusb_init() call
* All logging is now sent to to stderr (info was sent to stdout previously)
* Update log messages severity and avoid polluting log output on OS-X
* Add HID driver support on Windows
* Enable interchangeability of MSVC and MinGW DLLs
* Additional bug fixes and improvements

2012-05-08: v1.0.11
* Revert removal of critical Windows event handling that was introduced in 1.0.10
* Fix a possible deadlock in Windows when submitting transfers
* Add timestamped logging
* Add NetBSD support (experimental) and BSD libusb_get_device_speed() data
* Add bootstrap.sh alongside autogen.sh (bootstrap.sh doesn't invoke configure)
* Search for device nodes in /dev for Android support
* Other bug fixes

2012-04-17: v1.0.10
* Public release
* Add libusb_get_version
* Add Visual Studio 2010 project files
* Some Windows code cleanup
* Fix xusb sample warnings 

2012-04-02: v1.0.9
* First libusbx release
* Add libusb_get_device_speed (all, except BSD) and libusb_error_name
* Add Windows support (WinUSB driver only)
* Add OpenBSD support
* Add xusb sample
* Tons of bug fixes

2010-05-07: v1.0.8
* Bug fixes

2010-04-19: v1.0.7
* Bug fixes and documentation tweaks
* Add more interface class definitions

2009-11-22: v1.0.6
* Bug fixes
* Increase libusb_handle_events() timeout to 60s for powersaving

2009-11-15: v1.0.5
 * Use timerfd when available for timer management
 * Small fixes/updates

2009-11-06: v1.0.4 release
 * Bug fixes including transfer locking to fix some potential threading races
 * More flexibility with clock types on Linux
 * Use new bulk continuation tracking in Linux 2.6.32 for improved handling
   of short/failed transfers

2009-08-27: v1.0.3 release
 * Bug fixes
 * Add libusb_get_max_iso_packet_size()

2009-06-13: v1.0.2 release
 * Bug fixes

2009-05-12: v1.0.1 release
 * Bug fixes
 * Darwin backend

2008-12-13: v1.0.0 release
 * Bug fixes

2008-11-21: v0.9.4 release
 * Bug fixes
 * Add libusb_attach_kernel_driver()

2008-08-23: v0.9.3 release
 * Bug fixes

2008-07-19: v0.9.2 release
 * Bug fixes

2008-06-28: v0.9.1 release
 * Bug fixes
 * Introduce contexts to the API
 * Compatibility with new Linux kernel features

2008-05-25: v0.9.0 release
 * First libusb-1.0 beta release

~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

APPENDIX A - How to maintain code compatibility with versions of libusb and
libusb that use MaxPower:

If you must to maintain compatibility with versions of the library that aren't
using the bMaxPower attribute in struct libusb_config_descriptor, the 
recommended way is to use the new LIBUSB_API_VERSION macro with an #ifdef.
For instance, if your code was written as follows:

  if (dev->config[0].MaxPower < 250)

Then you should modify it to have:

#if defined(LIBUSB_API_VERSION) && (LIBUSB_API_VERSION >= 0x01000100)
  if (dev->config[0].bMaxPower < 250)
#else
  if (dev->config[0].MaxPower < 250)
#endif
