Log Message:
0.21.4 (2014-11-04)

    Fix credentials callback not set when pushing #431 #435 #437 #438
    Fix Repository.diff(...) when treeish is "empty" #432
    New Reference.peel(...) renders Reference.get_object() obsolete #434
    New, authenticate using ssh agent #424
    New Repository.merge_commits(...) #445
    Make it easier to run when libgit2 not in a standard location #441
    Documentation: review install chapter
    Documentation: many corrections #427 #429 #439 #440 #442 #443 #444

0.21.3 (2014-09-15)

Breaking changes:

    Now Repository.blame(...) returns Oid instead of string #413
    New Reference.set_target(...) replaces the Reference.target setter and \ 
Reference.log_append(...) #414
    New Repository.set_head(...) replaces the Repository.head setter #414
    Repository.merge(...) now uses the SAFE_CREATE strategy by default #417

Other changes:

    New Remote.delete() #418 #420
    New Repository.write_archive(...) #421
    Now Repository.checkout(...) accepts branch objects #408
    Fix refcount leak in remotes #403 #404 #419
    Various fixes to clone_repository(...) #399 #411 #425 #426
    Fix build error in Python 3 #401
    Now pip install pygit2 installs cffi first #380 #407
    Add support for pypy3 #422
    Documentation improvements #398 #409

0.21.2 (2014-08-09)

    Fix regression with Python 2, IndexEntry.path returns str (bytes in Python 2 \ 
and unicode in Python 3)
    Get back IndexEntry.oid for backwards compatibility
    Config, iterate over the keys (instead of the key/value pairs) #395
    Diff.find_similar supports new threshold arguments #396
    Optimization, do not load the object when expanding an oid prefix #397

0.21.1 (2014-07-22)

    Install fix #382
    Documentation improved, including #383 #385 #388
    Documentation, use the read-the-docs theme #387
    Coding style improvements #392
    New Repository.state_cleanup() #386
    New Index.conflicts #345 #389
    New checkout option to define the target directory #390

Backward incompatible changes:

    Now the checkout strategy must be a keyword argument.

    Change Repository.checkout(refname, strategy) to \ 
Repository.checkout(refname, strategy=strategy)

    Idem for checkout_head, checkout_index and checkout_tree

0.21.0 (2014-06-27)

Highlights:

    Drop official support for Python 2.6, and add support for Python 3.4 #376
    Upgrade to libgit2 v0.21.0 #374
    Start using cffi #360 #361

Backward incompatible changes:

    Replace oid by id through the API to follow libgit2 conventions.
    Merge API overhaul following changes in libgit2.
    New Remote.rename(...) replaces Remote.name = ...
    Now Remote.fetch() returns a TransferProgress object.
    Now Config.get_multivar(...) returns an iterator instead of a list.

New features:

    New Config.snapshot() and Repository.config_snapshot()
    New Config methods: get_bool(...), get_int(...), parse_bool(...) and \ 
parse_int(...) #357
    Blob: implement the memory buffer interface #362
    New clone_into(...) function #368
    Now Index can be used alone, without a repository #372
    Add more options to init_repository #347
    Support Repository.workdir = ... and support setting detached heads \ 
Repository.head = <Oid> #377

Other:

    Fix again build with VS2008 #364
    Fix Blob.diff(...) and Blob.diff_to_buffer(...) arguments passing #366
    Fail gracefully when compiling against the wrong version of libgit2 #365
    Several documentation improvements and updates #359 #375 #378