Overview of Changes in GLib 1.3.7:

* Integrate GClosure support into the main loop [Owen Taylor]
* More GSignal convenience functions (macros) [Sven Neumann, Tim Janik]
* Introduced weak references for GObject [James Henstridge, Sven, Tim] 
* Minor hash table optimizations
* Main loop and threading improvements [Sebastian Wilhelmi]
* Added g_ascii_* functions to be used for locale insensitive UTF-8
  compliant code instead of old string functions  [Darin Adler, Alex Larsson]
* Add functions for Unicode case-conversion, normalization, and 
  collation [Owen]* GString improvements [Owen]
* Reworked the GIOChannel code [Hidetoshi Tajima, Ron Steinke]
* Removed glib-config-2.0 in favour of pkgconfig [Sebastian]
* Make code 64bit clean [Mark Murnane]
* More G_CONST_RETURN fixes
* Many improvements to the win32 code [Tor Lillqvist, Hans Breuer]
* Miscellaneous bug and API fixes

Overview of Changes in GLib 1.3.6:

* Threads have a "return value" from g_thread_join
* Removed ability to adjust thread stack size
* Prefix warnings with progname/PID by default, change toggle for this to 
  be an env variable G_MESSAGES_PREFIXED not a compile-time option
* GMarkup speedups
* GDate const, convenience fixups
* Include test cases that headers are compilable by C++ compiler
* Add ability to spawn processes with argv[0] != executable path.
* g_strstr_len, g_strrstr, g_strrstr_len
* Add length argument to g_utf8_strchr and g_utf8_strrchr.
* Misc bug fixes

Overview of Changes in GLib 1.3.5:

* Added an installed glib-mkenums Perl program for parsing enumeration
  declarations from header files.
* Mark some additional deprecated functions.
* Bug and Portability fixes

Overview of Changes in GLib 1.3.4:

* Efficiency improvements for GThreadPool
* A few bug fixes
* Build fixes
* Documentation improvements

Overview of Changes in GLib 1.3.3:

* More user_data support in various functions.
* Main loop API revamps to support per-thread main loops.
* Unicode handling improvements.
* Implemented debugging traps.
* G_CONST_RETURN specification all over the place.
* Various new small utility functions.
* Random number generator precision improvements.
* New configure option --disable-mem-pools.
* Many Win32 improvements.
* Added g_try_malloc() friends varinats.
* Many documentation improvements.
* Many threading improvements, support for dynamic allocation
  of static mutexes.
* GHookLIst API cleanups.
* Improved format support of GDate parser.
* String function speed improvements with new g_stpcpy().
* Hashtable API additions.
* New GPatternSpec for shell-style pattern matching (from GtkPatternSpec).
* Optimizations, cleanups, bug fixes.

Overview of Changes in GLib 1.3.2:

GLib:

* Win32 build improvements  [Tor]
* Improvements to error reporting  
  (g_critical(), g_return_if_reached()) [Darin]
* Add g_strlcpy/g_strlcat  [David Wheeler]
* New IO channel implementation for Win32  [Tor] 
* Make g_array_free, g_string_free return pointer to memory requested
  not to be freed.  [Darin]
* Added GError based error reporting for thread functions.  [Sebastian]
* Moved reference docs into GLib distribution. [Owen]
* Added g_convert() for doing convenient character set conversions based
  on iconv. (GLib now requires libiconv or a native iconv.) [Havoc/Owen]
* Various Unicode handling additions (g_ucs4_to_utf8, g_utf8_validate(),
  g_{locale,filename}_{to,from}_utf8)  [Robert/Havoc/Owen]
* Portability fixes for threading.  [Sebastian]
* Added convenient functions for launching new processes (g_spawn_*),
  and shell quoting/unquoting functions.  [Havoc]
* Split glib.h into many headers.  [Sebastian]
* Added a simple callback-based parser for XML-like files (GMarkup).  [Havoc]
* Fixed confusions between comparison functions that return <0, 0, >0
  and equaility functions that return FALSE,TRUE.  [Sebastian]
* Added safe/portable temporary file manipulation functions.  [Tor]
* autoconf improvements.  [Raja]
* Many documentation improvements.
* Bug fixes.

GObject:

* Added boxed and pointer types.  [Tim/Jonathan]
* Added callback abstraction (GClosure)  [Tim]
* Added signal system (GSignal)  [Tim]
* Make GTypePlugin an interface  [Tim]
* Added GTypeModule - a simple GTypePlugin instantiation  [Owen]
* Bug fixes.

What's new in GLib 1.3.1:

* New GObject library added including object system based on
  the GTK+ object system. 
* Functions for getting the properties of Unicode characters, 
  computing the canonical decomposition and ordering combining
  characters aand manipulating UTF-8 string manipulation based
  on libunicode.
* GString now properly handles embedded nuls.
* Multiple fixes from the 1.2.x branch.
* Upgrade to libtool 1.3.3
* Full thread support (thread creation and destruction).
* BeOS port, BeOS dynamic modules.
* Many improvements to the Windows ports.
* Improvements to the OS/2 port, OS/2 module support.
* Double ended queue implementation.
* GLib macros for printf() formatting, e.g. G_GULONG_FORMAT = "lu"
* New configure option --enable-msg-prefix to prefix messages, warnings
  et ceteri with the program name and the process id.
* New thread-safe random number generator Mersenne Twister.
* g_strcompress() added, g_strescape() had a slight API change, and
  more tightly defined semantics.
* the g_string(x) macro has been removed, #x may be used instead.