diff --git a/ChangeLog.rst b/ChangeLog.rst
index ed0f92e5a3dcfbeb3b6c28d439b4c10ff56cfba8..b6158c3343b1092804097ada4e09c763ee661664 100644
--- a/ChangeLog.rst
+++ b/ChangeLog.rst
@@ -1,3 +1,39 @@
+0.5.6
+======
+
+* Fix fallback.Unpacker.feed() dropped unused data from buffer (#287)
+* Resurrect fallback.unpack() and _unpacker.unpack().
+  They were removed at 0.5.5 but it breaks backward compatibility. (#288, #290)
+
+0.5.5
+======
+
+* Fix memory leak in pure Python Unpacker.feed() (#283)
+* Fix unpack() didn't support `raw` option (#285)
+
+0.5.4
+======
+
+* Undeprecate ``unicode_errors`` option. (#278)
+
+0.5.3
+======
+
+* Fixed regression when passing ``unicode_errors`` to Packer but not ``encoding``. (#277)
+
+0.5.2
+======
+
+* Add ``raw`` option to Unpacker.  It is preferred way than ``encoding`` option.
+
+* Packer.pack() reset buffer on exception (#274)
+
+
+0.5.1
+======
+
+* Remove FutureWarning about use_bin_type option (#271)
+
 0.5.0
 ======
 
diff --git a/Makefile b/Makefile
index 84decd80b69c09e8e4acd7c08fe2f4810a42a608..124f24379a802fdc385e9b9d78d553a90fd4e4f1 100644
--- a/Makefile
+++ b/Makefile
@@ -8,7 +8,8 @@ cython:
 
 .PHONY: test
 test:
-	py.test -v test
+	pytest -v test
+	MSGPACK_PUREPYTHON=1 pytest -v test
 
 .PHONY: serve-doc
 serve-doc: all
@@ -17,10 +18,16 @@ serve-doc: all
 .PHONY: clean
 clean:
 	rm -rf build
-	rm msgpack/*.so
+	rm -f msgpack/_packer.cpp
+	rm -f msgpack/_unpacker.cpp
 	rm -rf msgpack/__pycache__
 	rm -rf test/__pycache__
 
+.PHONY: update-docker
+update-docker:
+	docker pull quay.io/pypa/manylinux1_i686
+	docker pull quay.io/pypa/manylinux1_x86_64
+
 .PHONY: linux-wheel
 linux-wheel:
 	docker run --rm -ti -v `pwd`:/project -w /project quay.io/pypa/manylinux1_i686   bash docker/buildwheel.sh
diff --git a/README.rst b/README.rst
index 01a8b2a42d91c45450a0d3aed9c1215f726e36d5..8925a65c410d8efb1e1e126ed7cc2addef7a3eac 100644
--- a/README.rst
+++ b/README.rst
@@ -10,8 +10,21 @@ MessagePack for Python
    :target: https://msgpack-python.readthedocs.io/en/latest/?badge=latest
    :alt: Documentation Status
 
-IMPORTANT: Upgrading from msgpack-0.4
---------------------------------------
+
+What's this
+-----------
+
+`MessagePack <https://msgpack.org/>`_ is an efficient binary serialization format.
+It lets you exchange data among multiple languages like JSON.
+But it's faster and smaller.
+This package provides CPython bindings for reading and writing MessagePack data.
+
+
+Very important notes for existing users
+---------------------------------------
+
+PyPI package name
+^^^^^^^^^^^^^^^^^
 
 TL;DR: When upgrading from msgpack-0.4 or earlier, don't do `pip install -U msgpack-python`.
 Do `pip uninstall msgpack-python; pip install msgpack` instead.
@@ -24,13 +37,37 @@ Sadly, this doesn't work for upgrade install.  After `pip install -U msgpack-pyt
 msgpack is removed and `import msgpack` fail.
 
 
-What's this
------------
+Deprecating encoding option
+^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+
+encoding and unicode_errors options are deprecated.
+
+In case of packer, use UTF-8 always.  Storing other than UTF-8 is not recommended.
+
+For backward compatibility, you can use ``use_bin_type=False`` and pack ``bytes``
+object into msgpack raw type.
+
+In case of unpacker, there is new ``raw`` option.  It is ``True`` by default
+for backward compatibility, but it is changed to ``False`` in near future.
+You can use ``raw=False`` instead of ``encoding='utf-8'``.
+
+Planned backward incompatible changes
+^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+
+When msgpack 1.0, I planning these breaking changes:
+
+* packer and unpacker: Remove ``encoding`` and ``unicode_errors`` option.
+* packer: Change default of ``use_bin_type`` option from False to True.
+* unpacker: Change default of ``raw`` option from True to False.
+* unpacker: Reduce all ``max_xxx_len`` options for typical usage.
+* unpacker: Remove ``write_bytes`` option from all methods.
+
+To avoid these breaking changes breaks your application, please:
+
+* Don't use deprecated options.
+* Pass ``use_bin_type`` and ``raw`` options explicitly.
+* If your application handle large (>1MB) data, specify ``max_xxx_len`` options too.
 
-`MessagePack <https://msgpack.org/>`_ is an efficient binary serialization format.
-It lets you exchange data among multiple languages like JSON.
-But it's faster and smaller.
-This package provides CPython bindings for reading and writing MessagePack data.
 
 Install
 -------
@@ -76,14 +113,14 @@ msgpack provides ``dumps`` and ``loads`` as an alias for compatibility with
    >>> import msgpack
    >>> msgpack.packb([1, 2, 3], use_bin_type=True)
    '\x93\x01\x02\x03'
-   >>> msgpack.unpackb(_)
+   >>> msgpack.unpackb(_, raw=False)
    [1, 2, 3]
 
 ``unpack`` unpacks msgpack's array to Python's list, but can also unpack to tuple:
 
 .. code-block:: pycon
 
-   >>> msgpack.unpackb(b'\x93\x01\x02\x03', use_list=False)
+   >>> msgpack.unpackb(b'\x93\x01\x02\x03', use_list=False, raw=False)
    (1, 2, 3)
 
 You should always specify the ``use_list`` keyword argument for backward compatibility.
@@ -109,7 +146,7 @@ stream (or from bytes provided through its ``feed`` method).
 
    buf.seek(0)
 
-   unpacker = msgpack.Unpacker(buf)
+   unpacker = msgpack.Unpacker(buf, raw=False)
    for unpacked in unpacker:
        print(unpacked)
 
@@ -142,7 +179,7 @@ It is also possible to pack/unpack custom data types. Here is an example for
 
 
     packed_dict = msgpack.packb(useful_dict, default=encode_datetime, use_bin_type=True)
-    this_dict_again = msgpack.unpackb(packed_dict, object_hook=decode_datetime)
+    this_dict_again = msgpack.unpackb(packed_dict, object_hook=decode_datetime, raw=False)
 
 ``Unpacker``'s ``object_hook`` callback receives a dict; the
 ``object_pairs_hook`` callback may instead be used to receive a list of
@@ -172,7 +209,7 @@ It is also possible to pack/unpack custom data types using the **ext** type.
     ...
     >>> data = array.array('d', [1.2, 3.4])
     >>> packed = msgpack.packb(data, default=default, use_bin_type=True)
-    >>> unpacked = msgpack.unpackb(packed, ext_hook=ext_hook)
+    >>> unpacked = msgpack.unpackb(packed, ext_hook=ext_hook, raw=False)
     >>> data == unpacked
     True
 
@@ -217,14 +254,10 @@ Early versions of msgpack didn't distinguish string and binary types (like Pytho
 The type for representing both string and binary types was named **raw**.
 
 For backward compatibility reasons, msgpack-python will still default all
-strings to byte strings, unless you specify the `use_bin_type=True` option in
+strings to byte strings, unless you specify the ``use_bin_type=True`` option in
 the packer. If you do so, it will use a non-standard type called **bin** to
 serialize byte arrays, and **raw** becomes to mean **str**. If you want to
-distinguish **bin** and **raw** in the unpacker, specify `encoding='utf-8'`.
-
-**In future version, default value of ``use_bin_type`` will be changed to ``True``.
-To avoid this change will break your code, you must specify it explicitly
-even when you want to use old format.**
+distinguish **bin** and **raw** in the unpacker, specify ``raw=False``.
 
 Note that Python 2 defaults to byte-arrays over Unicode strings:
 
@@ -234,7 +267,7 @@ Note that Python 2 defaults to byte-arrays over Unicode strings:
     >>> msgpack.unpackb(msgpack.packb([b'spam', u'eggs']))
     ['spam', 'eggs']
     >>> msgpack.unpackb(msgpack.packb([b'spam', u'eggs'], use_bin_type=True),
-                        encoding='utf-8')
+                        raw=False)
     ['spam', u'eggs']
 
 This is the same code in Python 3 (same behaviour, but Python 3 has a
@@ -246,7 +279,7 @@ different default):
     >>> msgpack.unpackb(msgpack.packb([b'spam', u'eggs']))
     [b'spam', b'eggs']
     >>> msgpack.unpackb(msgpack.packb([b'spam', u'eggs'], use_bin_type=True),
-                        encoding='utf-8')
+                        raw=False)
     [b'spam', 'eggs']
 
 
@@ -277,6 +310,7 @@ You can use ``gc.disable()`` when unpacking large message.
 
 use_list option
 ^^^^^^^^^^^^^^^
+
 List is the default sequence type of Python.
 But tuple is lighter than list.
 You can use ``use_list=False`` while unpacking when performance is important.
@@ -295,7 +329,7 @@ Test
 MessagePack uses `pytest` for testing.
 Run test with following command:
 
-    $ pytest -v test
+    $ make test
 
 
 ..
diff --git a/ci/runtests.bat b/ci/runtests.bat
index 9efea00c8f0c5375bde21536f55bec8bed66a110..02404679f06f1dcff49df607e9718537053ee654 100644
--- a/ci/runtests.bat
+++ b/ci/runtests.bat
@@ -3,5 +3,7 @@
 %PYTHON%\python.exe setup.py install
 %PYTHON%\python.exe -c "import sys; print(hex(sys.maxsize))"
 %PYTHON%\python.exe -c "from msgpack import _packer, _unpacker"
-%PYTHON%\python.exe -m pytest -v test
 %PYTHON%\python.exe setup.py bdist_wheel
+%PYTHON%\python.exe -m pytest -v test
+SET EL=%ERRORLEVEL%
+exit /b %EL%
diff --git a/debian/changelog b/debian/changelog
index 732366ad9f259fe7dfd4e2406b72440d2a961021..fffb1e3c64f35875a962b355a83139830935b2b5 100644
--- a/debian/changelog
+++ b/debian/changelog
@@ -1,3 +1,10 @@
+python-msgpack (0.5.6-1) unstable; urgency=medium
+
+  * Team upload
+  * New upstream release (Closes: #895733)
+
+ -- Gianfranco Costamagna <locutusofborg@debian.org>  Sun, 15 Apr 2018 18:44:47 +0200
+
 python-msgpack (0.5.1-3) unstable; urgency=medium
 
   [ Ondřej Nový ]
diff --git a/docker/runtests.sh b/docker/runtests.sh
index 11ef9f46833ea389908b901bbcf2c772174215a1..113b6307ae5f3ac8d4646ed9866e390477bc8d34 100755
--- a/docker/runtests.sh
+++ b/docker/runtests.sh
@@ -9,6 +9,6 @@ for V in cp36-cp36m cp35-cp35m cp27-cp27m cp27-cp27mu; do
     pushd test          # prevent importing msgpack package in current directory.
     $PYBIN/python -c 'import sys; print(hex(sys.maxsize))'
     $PYBIN/python -c 'from msgpack import _packer, _unpacker'
-    $PYBIN/py.test -v
+    $PYBIN/pytest -v .
     popd
 done
diff --git a/msgpack/__init__.py b/msgpack/__init__.py
index 6c5ae53273c747e86985dd3969fe9c963a98d3a8..3955a4143904ce80b1e5bf1a291f47f1bb4eb34c 100644
--- a/msgpack/__init__.py
+++ b/msgpack/__init__.py
@@ -19,13 +19,13 @@ class ExtType(namedtuple('ExtType', 'code data')):
 
 import os
 if os.environ.get('MSGPACK_PUREPYTHON'):
-    from msgpack.fallback import Packer, unpack, unpackb, Unpacker
+    from msgpack.fallback import Packer, unpackb, Unpacker
 else:
     try:
         from msgpack._packer import Packer
-        from msgpack._unpacker import unpack, unpackb, Unpacker
+        from msgpack._unpacker import unpackb, Unpacker
     except ImportError:
-        from msgpack.fallback import Packer, unpack, unpackb, Unpacker
+        from msgpack.fallback import Packer, unpackb, Unpacker
 
 
 def pack(o, stream, **kwargs):
@@ -46,6 +46,18 @@ def packb(o, **kwargs):
     """
     return Packer(**kwargs).pack(o)
 
+
+def unpack(stream, **kwargs):
+    """
+    Unpack an object from `stream`.
+
+    Raises `ExtraData` when `stream` contains extra bytes.
+    See :class:`Unpacker` for options.
+    """
+    data = stream.read()
+    return unpackb(data, **kwargs)
+
+
 # alias for compatibility to simplejson/marshal/pickle.
 load = unpack
 loads = unpackb
diff --git a/msgpack/_packer.pyx b/msgpack/_packer.pyx
index 13a18f6cae68731418aa5e4406b4df069bc224c9..225f24aecc3277dfdbb2feceb1a04c7799f5ada3 100644
--- a/msgpack/_packer.pyx
+++ b/msgpack/_packer.pyx
@@ -1,8 +1,9 @@
 # coding: utf-8
-#cython: embedsignature=True
+#cython: embedsignature=True, c_string_encoding=ascii
 
 from cpython cimport *
-#from cpython.exc cimport PyErr_WarnEx
+from cpython.version cimport PY_MAJOR_VERSION
+from cpython.exc cimport PyErr_WarnEx
 
 from msgpack.exceptions import PackValueError, PackOverflowError
 from msgpack import ExtType
@@ -13,6 +14,7 @@ cdef extern from "Python.h":
     int PyMemoryView_Check(object obj)
     int PyByteArray_Check(object obj)
     int PyByteArray_CheckExact(object obj)
+    char* PyUnicode_AsUTF8AndSize(object obj, Py_ssize_t *l) except NULL
 
 
 cdef extern from "pack.h":
@@ -37,9 +39,10 @@ cdef extern from "pack.h":
     int msgpack_pack_bin(msgpack_packer* pk, size_t l)
     int msgpack_pack_raw_body(msgpack_packer* pk, char* body, size_t l)
     int msgpack_pack_ext(msgpack_packer* pk, char typecode, size_t l)
+    int msgpack_pack_unicode(msgpack_packer* pk, object o, long long limit)
 
 cdef int DEFAULT_RECURSE_LIMIT=511
-cdef size_t ITEM_LIMIT = (2**32)-1
+cdef long long ITEM_LIMIT = (2**32)-1
 
 
 cdef inline int PyBytesLike_Check(object o):
@@ -87,17 +90,18 @@ cdef class Packer(object):
         This is useful when trying to implement accurate serialization
         for python types.
 
+    :param str unicode_errors:
+        Error handler for encoding unicode. (default: 'strict')
+
     :param str encoding:
         (deprecated) Convert unicode to bytes with this encoding. (default: 'utf-8')
-    :param str unicode_errors:
-        (deprecated) Error handler for encoding unicode. (default: 'strict')
     """
     cdef msgpack_packer pk
     cdef object _default
     cdef object _bencoding
     cdef object _berrors
-    cdef char *encoding
-    cdef char *unicode_errors
+    cdef const char *encoding
+    cdef const char *unicode_errors
     cdef bint strict_types
     cdef bool use_float
     cdef bint autoreset
@@ -110,9 +114,11 @@ cdef class Packer(object):
         self.pk.buf_size = buf_size
         self.pk.length = 0
 
-    def __init__(self, default=None, encoding='utf-8', unicode_errors='strict',
+    def __init__(self, default=None, encoding=None, unicode_errors=None,
                  bint use_single_float=False, bint autoreset=True, bint use_bin_type=False,
                  bint strict_types=False):
+        if encoding is not None:
+            PyErr_WarnEx(PendingDeprecationWarning, "encoding is deprecated.", 1)
         self.use_float = use_single_float
         self.strict_types = strict_types
         self.autoreset = autoreset
@@ -121,20 +127,21 @@ cdef class Packer(object):
             if not PyCallable_Check(default):
                 raise TypeError("default must be a callable.")
         self._default = default
+
+        self._bencoding = encoding
         if encoding is None:
-            self.encoding = NULL
+            if PY_MAJOR_VERSION < 3:
+                self.encoding = 'utf-8'
+            else:
+                self.encoding = NULL
+        else:
+            self.encoding = self._bencoding
+
+        self._berrors = unicode_errors
+        if unicode_errors is None:
             self.unicode_errors = NULL
         else:
-            if isinstance(encoding, unicode):
-                self._bencoding = encoding.encode('ascii')
-            else:
-                self._bencoding = encoding
-            self.encoding = PyBytes_AsString(self._bencoding)
-            if isinstance(unicode_errors, unicode):
-                self._berrors = unicode_errors.encode('ascii')
-            else:
-                self._berrors = unicode_errors
-            self.unicode_errors = PyBytes_AsString(self._berrors)
+            self.unicode_errors = self._berrors
 
     def __dealloc__(self):
         PyMem_Free(self.pk.buf)
@@ -149,7 +156,7 @@ cdef class Packer(object):
         cdef char* rawval
         cdef int ret
         cdef dict d
-        cdef size_t L
+        cdef Py_ssize_t L
         cdef int default_used = 0
         cdef bint strict_types = self.strict_types
         cdef Py_buffer view
@@ -201,16 +208,19 @@ cdef class Packer(object):
                 if ret == 0:
                     ret = msgpack_pack_raw_body(&self.pk, rawval, L)
             elif PyUnicode_CheckExact(o) if strict_types else PyUnicode_Check(o):
-                if not self.encoding:
-                    raise TypeError("Can't encode unicode string: no encoding is specified")
-                o = PyUnicode_AsEncodedString(o, self.encoding, self.unicode_errors)
-                L = len(o)
-                if L > ITEM_LIMIT:
-                    raise PackValueError("unicode string is too large")
-                rawval = o
-                ret = msgpack_pack_raw(&self.pk, L)
-                if ret == 0:
-                    ret = msgpack_pack_raw_body(&self.pk, rawval, L)
+                if self.encoding == NULL and self.unicode_errors == NULL:
+                    ret = msgpack_pack_unicode(&self.pk, o, ITEM_LIMIT);
+                    if ret == -2:
+                        raise PackValueError("unicode string is too large")
+                else:
+                    o = PyUnicode_AsEncodedString(o, self.encoding, self.unicode_errors)
+                    L = len(o)
+                    if L > ITEM_LIMIT:
+                        raise PackValueError("unicode string is too large")
+                    ret = msgpack_pack_raw(&self.pk, L)
+                    if ret == 0:
+                        rawval = o
+                        ret = msgpack_pack_raw_body(&self.pk, rawval, L)
             elif PyDict_CheckExact(o):
                 d = <dict>o
                 L = len(d)
@@ -273,11 +283,13 @@ cdef class Packer(object):
 
     cpdef pack(self, object obj):
         cdef int ret
-        ret = self._pack(obj, DEFAULT_RECURSE_LIMIT)
-        if ret == -1:
-            raise MemoryError
-        elif ret:  # should not happen.
-            raise TypeError
+        try:
+            ret = self._pack(obj, DEFAULT_RECURSE_LIMIT)
+        except:
+            self.pk.length = 0
+            raise
+        if ret:  # should not happen.
+            raise RuntimeError("internal error")
         if self.autoreset:
             buf = PyBytes_FromStringAndSize(self.pk.buf, self.pk.length)
             self.pk.length = 0
diff --git a/msgpack/_unpacker.pyx b/msgpack/_unpacker.pyx
index 564749e702837383a9d1f31b4bb3cf43b1a549ed..d7fa5bc6c08ba447f35cee3d3be015d558d3df8c 100644
--- a/msgpack/_unpacker.pyx
+++ b/msgpack/_unpacker.pyx
@@ -1,6 +1,7 @@
 # coding: utf-8
-#cython: embedsignature=True
+#cython: embedsignature=True, c_string_encoding=ascii
 
+from cpython.version cimport PY_MAJOR_VERSION
 from cpython.bytes cimport (
     PyBytes_AsString,
     PyBytes_FromStringAndSize,
@@ -43,8 +44,9 @@ from msgpack import ExtType
 cdef extern from "unpack.h":
     ctypedef struct msgpack_user:
         bint use_list
-        PyObject* object_hook
+        bint raw
         bint has_pairs_hook # call object_hook with k-v pairs
+        PyObject* object_hook
         PyObject* list_hook
         PyObject* ext_hook
         char *encoding
@@ -73,12 +75,14 @@ cdef extern from "unpack.h":
 cdef inline init_ctx(unpack_context *ctx,
                      object object_hook, object object_pairs_hook,
                      object list_hook, object ext_hook,
-                     bint use_list, char* encoding, char* unicode_errors,
+                     bint use_list, bint raw,
+                     const char* encoding, const char* unicode_errors,
                      Py_ssize_t max_str_len, Py_ssize_t max_bin_len,
                      Py_ssize_t max_array_len, Py_ssize_t max_map_len,
                      Py_ssize_t max_ext_len):
     unpack_init(ctx)
     ctx.user.use_list = use_list
+    ctx.user.raw = raw
     ctx.user.object_hook = ctx.user.list_hook = <PyObject*>NULL
     ctx.user.max_str_len = max_str_len
     ctx.user.max_bin_len = max_bin_len
@@ -155,7 +159,8 @@ cdef inline int get_data_from_buffer(object obj,
         return 1
 
 def unpackb(object packed, object object_hook=None, object list_hook=None,
-            bint use_list=1, encoding=None, unicode_errors="strict",
+            bint use_list=True, bint raw=True,
+            encoding=None, unicode_errors=None,
             object_pairs_hook=None, ext_hook=ExtType,
             Py_ssize_t max_str_len=2147483647, # 2**32-1
             Py_ssize_t max_bin_len=2147483647,
@@ -176,25 +181,21 @@ def unpackb(object packed, object object_hook=None, object list_hook=None,
     cdef Py_buffer view
     cdef char* buf = NULL
     cdef Py_ssize_t buf_len
-    cdef char* cenc = NULL
-    cdef char* cerr = NULL
+    cdef const char* cenc = NULL
+    cdef const char* cerr = NULL
     cdef int new_protocol = 0
 
-    get_data_from_buffer(packed, &view, &buf, &buf_len, &new_protocol)
-
-    try:
-        if encoding is not None:
-            if isinstance(encoding, unicode):
-                encoding = encoding.encode('ascii')
-            cenc = PyBytes_AsString(encoding)
+    if encoding is not None:
+        PyErr_WarnEx(PendingDeprecationWarning, "encoding is deprecated, Use raw=False instead.", 1)
+        cenc = encoding
 
-        if unicode_errors is not None:
-            if isinstance(unicode_errors, unicode):
-                unicode_errors = unicode_errors.encode('ascii')
-            cerr = PyBytes_AsString(unicode_errors)
+    if unicode_errors is not None:
+        cerr = unicode_errors
 
+    get_data_from_buffer(packed, &view, &buf, &buf_len, &new_protocol)
+    try:
         init_ctx(&ctx, object_hook, object_pairs_hook, list_hook, ext_hook,
-                 use_list, cenc, cerr,
+                 use_list, raw, cenc, cerr,
                  max_str_len, max_bin_len, max_array_len, max_map_len, max_ext_len)
         ret = unpack_construct(&ctx, buf, buf_len, &off)
     finally:
@@ -210,30 +211,12 @@ def unpackb(object packed, object object_hook=None, object list_hook=None,
     raise UnpackValueError("Unpack failed: error = %d" % (ret,))
 
 
-def unpack(object stream, object object_hook=None, object list_hook=None,
-           bint use_list=1, encoding=None, unicode_errors="strict",
-           object_pairs_hook=None, ext_hook=ExtType,
-           Py_ssize_t max_str_len=2147483647, # 2**32-1
-           Py_ssize_t max_bin_len=2147483647,
-           Py_ssize_t max_array_len=2147483647,
-           Py_ssize_t max_map_len=2147483647,
-           Py_ssize_t max_ext_len=2147483647):
-    """
-    Unpack an object from `stream`.
-
-    Raises `ValueError` when `stream` has extra bytes.
-
-    See :class:`Unpacker` for options.
-    """
-    return unpackb(stream.read(), use_list=use_list,
-                   object_hook=object_hook, object_pairs_hook=object_pairs_hook, list_hook=list_hook,
-                   encoding=encoding, unicode_errors=unicode_errors, ext_hook=ext_hook,
-                   max_str_len=max_str_len,
-                   max_bin_len=max_bin_len,
-                   max_array_len=max_array_len,
-                   max_map_len=max_map_len,
-                   max_ext_len=max_ext_len,
-                   )
+def unpack(object stream, **kwargs):
+    PyErr_WarnEx(
+        PendingDeprecationWarning,
+        "Direct calling implementation's unpack() is deprecated, Use msgpack.unpack() or unpackb() instead.", 1)
+    data = stream.read()
+    return unpackb(data, **kwargs)
 
 
 cdef class Unpacker(object):
@@ -252,6 +235,16 @@ cdef class Unpacker(object):
         If true, unpack msgpack array to Python list.
         Otherwise, unpack to Python tuple. (default: True)
 
+    :param bool raw:
+        If true, unpack msgpack raw to Python bytes (default).
+        Otherwise, unpack to Python str (or unicode on Python 2) by decoding
+        with UTF-8 encoding (recommended).
+        Currently, the default is true, but it will be changed to false in
+        near future.  So you must specify it explicitly for keeping backward
+        compatibility.
+
+        *encoding* option which is deprecated overrides this option.
+
     :param callable object_hook:
         When specified, it should be callable.
         Unpacker calls it with a dict argument after unpacking msgpack map.
@@ -262,14 +255,6 @@ cdef class Unpacker(object):
         Unpacker calls it with a list of key-value pairs after unpacking msgpack map.
         (See also simplejson)
 
-    :param str encoding:
-        Encoding used for decoding msgpack raw.
-        If it is None (default), msgpack raw is deserialized to Python bytes.
-
-    :param str unicode_errors:
-        Used for decoding msgpack raw with *encoding*.
-        (default: `'strict'`)
-
     :param int max_buffer_size:
         Limits size of data waiting unpacked.  0 means system's INT_MAX (default).
         Raises `BufferFull` exception when it is insufficient.
@@ -287,16 +272,24 @@ cdef class Unpacker(object):
     :param int max_map_len:
         Limits max length of map. (default: 2**31-1)
 
+    :param str encoding:
+        Deprecated, use raw instead.
+        Encoding used for decoding msgpack raw.
+        If it is None (default), msgpack raw is deserialized to Python bytes.
+
+    :param str unicode_errors:
+        Error handler used for decoding str type.  (default: `'strict'`)
 
-    example of streaming deserialize from file-like object::
 
-        unpacker = Unpacker(file_like)
+    Example of streaming deserialize from file-like object::
+
+        unpacker = Unpacker(file_like, raw=False)
         for o in unpacker:
             process(o)
 
-    example of streaming deserialize from socket::
+    Example of streaming deserialize from socket::
 
-        unpacker = Unpacker()
+        unpacker = Unpacker(raw=False)
         while True:
             buf = sock.recv(1024**2)
             if not buf:
@@ -324,17 +317,18 @@ cdef class Unpacker(object):
         PyMem_Free(self.buf)
         self.buf = NULL
 
-    def __init__(self, file_like=None, Py_ssize_t read_size=0, bint use_list=1,
+    def __init__(self, file_like=None, Py_ssize_t read_size=0,
+                 bint use_list=True, bint raw=True,
                  object object_hook=None, object object_pairs_hook=None, object list_hook=None,
-                 encoding=None, unicode_errors='strict', int max_buffer_size=0,
+                 encoding=None, unicode_errors=None, int max_buffer_size=0,
                  object ext_hook=ExtType,
                  Py_ssize_t max_str_len=2147483647, # 2**32-1
                  Py_ssize_t max_bin_len=2147483647,
                  Py_ssize_t max_array_len=2147483647,
                  Py_ssize_t max_map_len=2147483647,
                  Py_ssize_t max_ext_len=2147483647):
-        cdef char *cenc=NULL,
-        cdef char *cerr=NULL
+        cdef const char *cenc=NULL,
+        cdef const char *cerr=NULL
 
         self.object_hook = object_hook
         self.object_pairs_hook = object_pairs_hook
@@ -363,25 +357,16 @@ cdef class Unpacker(object):
         self.stream_offset = 0
 
         if encoding is not None:
-            if isinstance(encoding, unicode):
-                self.encoding = encoding.encode('ascii')
-            elif isinstance(encoding, bytes):
-                self.encoding = encoding
-            else:
-                raise TypeError("encoding should be bytes or unicode")
-            cenc = PyBytes_AsString(self.encoding)
+            PyErr_WarnEx(PendingDeprecationWarning, "encoding is deprecated, Use raw=False instead.", 1)
+            self.encoding = encoding
+            cenc = encoding
 
         if unicode_errors is not None:
-            if isinstance(unicode_errors, unicode):
-                self.unicode_errors = unicode_errors.encode('ascii')
-            elif isinstance(unicode_errors, bytes):
-                self.unicode_errors = unicode_errors
-            else:
-                raise TypeError("unicode_errors should be bytes or unicode")
-            cerr = PyBytes_AsString(self.unicode_errors)
+            self.unicode_errors = unicode_errors
+            cerr = unicode_errors
 
         init_ctx(&self.ctx, object_hook, object_pairs_hook, list_hook,
-                 ext_hook, use_list, cenc, cerr,
+                 ext_hook, use_list, raw, cenc, cerr,
                  max_str_len, max_bin_len, max_array_len,
                  max_map_len, max_ext_len)
 
diff --git a/msgpack/_version.py b/msgpack/_version.py
index ecba3d88769bba171987d4bc34b4172c00a4ebd0..d28f0deb86cf2216f269b5ca7a8f45479076b43d 100644
--- a/msgpack/_version.py
+++ b/msgpack/_version.py
@@ -1 +1 @@
-version = (0, 5, 1)
+version = (0, 5, 6)
diff --git a/msgpack/fallback.py b/msgpack/fallback.py
index 5447b530b80df8ccb934ef98c10c36b30d0799c0..c0e5fd663f91a89123e393d06b3dc8a6473aca44 100644
--- a/msgpack/fallback.py
+++ b/msgpack/fallback.py
@@ -101,12 +101,9 @@ def _get_data_from_buffer(obj):
 
 
 def unpack(stream, **kwargs):
-    """
-    Unpack an object from `stream`.
-
-    Raises `ExtraData` when `packed` contains extra bytes.
-    See :class:`Unpacker` for options.
-    """
+    warnings.warn(
+        "Direct calling implementation's unpack() is deprecated, Use msgpack.unpack() or unpackb() instead.",
+        PendingDeprecationWarning)
     data = stream.read()
     return unpackb(data, **kwargs)
 
@@ -145,6 +142,16 @@ class Unpacker(object):
         If true, unpack msgpack array to Python list.
         Otherwise, unpack to Python tuple. (default: True)
 
+    :param bool raw:
+        If true, unpack msgpack raw to Python bytes (default).
+        Otherwise, unpack to Python str (or unicode on Python 2) by decoding
+        with UTF-8 encoding (recommended).
+        Currently, the default is true, but it will be changed to false in
+        near future.  So you must specify it explicitly for keeping backward
+        compatibility.
+
+        *encoding* option which is deprecated overrides this option.
+
     :param callable object_hook:
         When specified, it should be callable.
         Unpacker calls it with a dict argument after unpacking msgpack map.
@@ -183,13 +190,13 @@ class Unpacker(object):
 
     example of streaming deserialize from file-like object::
 
-        unpacker = Unpacker(file_like)
+        unpacker = Unpacker(file_like, raw=False)
         for o in unpacker:
             process(o)
 
     example of streaming deserialize from socket::
 
-        unpacker = Unpacker()
+        unpacker = Unpacker(raw=False)
         while True:
             buf = sock.recv(1024**2)
             if not buf:
@@ -199,15 +206,24 @@ class Unpacker(object):
                 process(o)
     """
 
-    def __init__(self, file_like=None, read_size=0, use_list=True,
+    def __init__(self, file_like=None, read_size=0, use_list=True, raw=True,
                  object_hook=None, object_pairs_hook=None, list_hook=None,
-                 encoding=None, unicode_errors='strict', max_buffer_size=0,
+                 encoding=None, unicode_errors=None, max_buffer_size=0,
                  ext_hook=ExtType,
                  max_str_len=2147483647, # 2**32-1
                  max_bin_len=2147483647,
                  max_array_len=2147483647,
                  max_map_len=2147483647,
                  max_ext_len=2147483647):
+
+        if encoding is not None:
+            warnings.warn(
+                "encoding is deprecated, Use raw=False instead.",
+                PendingDeprecationWarning)
+
+        if unicode_errors is None:
+            unicode_errors = 'strict'
+
         if file_like is None:
             self._feeding = True
         else:
@@ -234,6 +250,7 @@ class Unpacker(object):
         if read_size > self._max_buffer_size:
             raise ValueError("read_size must be smaller than max_buffer_size")
         self._read_size = read_size or min(self._max_buffer_size, 16*1024)
+        self._raw = bool(raw)
         self._encoding = encoding
         self._unicode_errors = unicode_errors
         self._use_list = use_list
@@ -265,6 +282,13 @@ class Unpacker(object):
         view = _get_data_from_buffer(next_bytes)
         if (len(self._buffer) - self._buff_i + len(view) > self._max_buffer_size):
             raise BufferFull
+
+        # Strip buffer before checkpoint before reading file.
+        if self._buf_checkpoint > 0:
+            del self._buffer[:self._buf_checkpoint]
+            self._buff_i -= self._buf_checkpoint
+            self._buf_checkpoint = 0
+
         self._buffer += view
 
     def _consume(self):
@@ -582,8 +606,10 @@ class Unpacker(object):
         if typ == TYPE_RAW:
             if self._encoding is not None:
                 obj = obj.decode(self._encoding, self._unicode_errors)
-            else:
+            elif self._raw:
                 obj = bytes(obj)
+            else:
+                obj = obj.decode('utf_8')
             return obj
         if typ == TYPE_EXT:
             return self._ext_hook(n, bytes(obj))
@@ -680,11 +706,21 @@ class Packer(object):
         (deprecated) Convert unicode to bytes with this encoding. (default: 'utf-8')
 
     :param str unicode_errors:
-        (deprecated) Error handler for encoding unicode. (default: 'strict')
+        Error handler for encoding unicode. (default: 'strict')
     """
-    def __init__(self, default=None, encoding='utf-8', unicode_errors='strict',
+    def __init__(self, default=None, encoding=None, unicode_errors=None,
                  use_single_float=False, autoreset=True, use_bin_type=False,
                  strict_types=False):
+        if encoding is None:
+            encoding = 'utf_8'
+        else:
+            warnings.warn(
+                "encoding is deprecated, Use raw=False instead.",
+                PendingDeprecationWarning)
+
+        if unicode_errors is None:
+            unicode_errors = 'strict'
+
         self._strict_types = strict_types
         self._use_float = use_single_float
         self._autoreset = autoreset
@@ -808,7 +844,11 @@ class Packer(object):
             raise TypeError("Cannot serialize %r" % (obj, ))
 
     def pack(self, obj):
-        self._pack(obj)
+        try:
+            self._pack(obj)
+        except:
+            self._buffer = StringIO()  # force reset
+            raise
         ret = self._buffer.getvalue()
         if self._autoreset:
             self._buffer = StringIO()
diff --git a/msgpack/pack.h b/msgpack/pack.h
index 3bc21ea5deffaf464673ecf533c6f5d7940dd10a..4f3ce1d99ec3f4af779723d21d1a540111b9eb54 100644
--- a/msgpack/pack.h
+++ b/msgpack/pack.h
@@ -67,6 +67,53 @@ static inline int msgpack_pack_write(msgpack_packer* pk, const char *data, size_
 
 #include "pack_template.h"
 
+// return -2 when o is too long
+static inline int
+msgpack_pack_unicode(msgpack_packer *pk, PyObject *o, long long limit)
+{
+#if PY_MAJOR_VERSION >= 3
+    assert(PyUnicode_Check(o));
+
+    Py_ssize_t len;
+    const char* buf = PyUnicode_AsUTF8AndSize(o, &len);
+    if (buf == NULL)
+        return -1;
+
+    if (len > limit) {
+        return -2;
+    }
+
+    int ret = msgpack_pack_raw(pk, len);
+    if (ret) return ret;
+
+    return msgpack_pack_raw_body(pk, buf, len);
+#else
+    PyObject *bytes;
+    Py_ssize_t len;
+    int ret;
+
+    // py2
+    bytes = PyUnicode_AsUTF8String(o);
+    if (bytes == NULL)
+        return -1;
+
+    len = PyString_GET_SIZE(bytes);
+    if (len > limit) {
+        Py_DECREF(bytes);
+        return -2;
+    }
+
+    ret = msgpack_pack_raw(pk, len);
+    if (ret) {
+        Py_DECREF(bytes);
+        return -1;
+    }
+    ret = msgpack_pack_raw_body(pk, PyString_AS_STRING(bytes), len);
+    Py_DECREF(bytes);
+    return ret;
+#endif
+}
+
 #ifdef __cplusplus
 }
 #endif
diff --git a/msgpack/unpack.h b/msgpack/unpack.h
index da2cfb6aa2370cd8b355ca66abc0b860d4498150..63e5543b559818d377aa51ab9493b163579fdaa2 100644
--- a/msgpack/unpack.h
+++ b/msgpack/unpack.h
@@ -20,9 +20,10 @@
 #include "unpack_define.h"
 
 typedef struct unpack_user {
-    int use_list;
-    PyObject *object_hook;
+    bool use_list;
+    bool raw;
     bool has_pairs_hook;
+    PyObject *object_hook;
     PyObject *list_hook;
     PyObject *ext_hook;
     const char *encoding;
@@ -225,10 +226,13 @@ static inline int unpack_callback_raw(unpack_user* u, const char* b, const char*
     }
 
     PyObject *py;
-    if(u->encoding) {
+
+    if (u->encoding) {
         py = PyUnicode_Decode(p, l, u->encoding, u->unicode_errors);
-    } else {
+    } else if (u->raw) {
         py = PyBytes_FromStringAndSize(p, l);
+    } else {
+        py = PyUnicode_DecodeUTF8(p, l, u->unicode_errors);
     }
     if (!py)
         return -1;
diff --git a/test/test_limits.py b/test/test_limits.py
index 197ef4615e3c1581dbff33e3c9023a8d2d3a23a4..74e48c19aebc86ae31eb8a8b282cf655ff5e1e80 100644
--- a/test/test_limits.py
+++ b/test/test_limits.py
@@ -39,11 +39,11 @@ def test_max_str_len():
     d = 'x' * 3
     packed = packb(d)
 
-    unpacker = Unpacker(max_str_len=3, encoding='utf-8')
+    unpacker = Unpacker(max_str_len=3, raw=False)
     unpacker.feed(packed)
     assert unpacker.unpack() == d
 
-    unpacker = Unpacker(max_str_len=2, encoding='utf-8')
+    unpacker = Unpacker(max_str_len=2, raw=False)
     with pytest.raises(UnpackValueError):
         unpacker.feed(packed)
         unpacker.unpack()
diff --git a/test/test_pack.py b/test/test_pack.py
index ac931038fc962e2df30d51a700ef18996fe74bd1..b447f9c38631672ff2a3275267362d4b941690cf 100644
--- a/test/test_pack.py
+++ b/test/test_pack.py
@@ -31,14 +31,14 @@ def testPack():
 def testPackUnicode():
     test_data = ["", "abcd", ["defgh"], "Русский текст"]
     for td in test_data:
-        re = unpackb(packb(td, encoding='utf-8'), use_list=1, encoding='utf-8')
+        re = unpackb(packb(td), use_list=1, raw=False)
         assert re == td
-        packer = Packer(encoding='utf-8')
+        packer = Packer()
         data = packer.pack(td)
-        re = Unpacker(BytesIO(data), encoding=str('utf-8'), use_list=1).unpack()
+        re = Unpacker(BytesIO(data), raw=False, use_list=1).unpack()
         assert re == td
 
-def testPackUTF32():
+def testPackUTF32():  # deprecated
     try:
         test_data = [
             "",
@@ -66,26 +66,22 @@ def testPackByteArrays():
     for td in test_data:
         check(td)
 
-def testIgnoreUnicodeErrors():
+def testIgnoreUnicodeErrors(): # deprecated
     re = unpackb(packb(b'abc\xeddef'), encoding='utf-8', unicode_errors='ignore', use_list=1)
     assert re == "abcdef"
 
 def testStrictUnicodeUnpack():
     with raises(UnicodeDecodeError):
-        unpackb(packb(b'abc\xeddef'), encoding='utf-8', use_list=1)
+        unpackb(packb(b'abc\xeddef'), raw=False, use_list=1)
 
-def testStrictUnicodePack():
+def testStrictUnicodePack():  # deprecated
     with raises(UnicodeEncodeError):
         packb("abc\xeddef", encoding='ascii', unicode_errors='strict')
 
-def testIgnoreErrorsPack():
-    re = unpackb(packb("abcФФФdef", encoding='ascii', unicode_errors='ignore'), encoding='utf-8', use_list=1)
+def testIgnoreErrorsPack():  # deprecated
+    re = unpackb(packb("abcФФФdef", encoding='ascii', unicode_errors='ignore'), raw=False, use_list=1)
     assert re == "abcdef"
 
-def testNoEncoding():
-    with raises(TypeError):
-        packb("abc", encoding=None)
-
 def testDecodeBinary():
     re = unpackb(packb(b"abc"), encoding=None, use_list=1)
     assert re == b"abc"
diff --git a/test/test_stricttype.py b/test/test_stricttype.py
index 0f865c8353b87462b0f39929a49a250794b1d006..87e7c1ce1df9e0b18956d03d944c20178f9bcdfa 100644
--- a/test/test_stricttype.py
+++ b/test/test_stricttype.py
@@ -11,7 +11,7 @@ def test_namedtuple():
             return dict(o._asdict())
         raise TypeError('Unsupported type %s' % (type(o),))
     packed = packb(T(1, 42), strict_types=True, use_bin_type=True, default=default)
-    unpacked = unpackb(packed, encoding='utf-8')
+    unpacked = unpackb(packed, raw=False)
     assert unpacked == {'foo': 1, 'bar': 42}
 
 
@@ -32,7 +32,7 @@ def test_tuple():
         return o
 
     data = packb(t, strict_types=True, use_bin_type=True, default=default)
-    expected = unpackb(data, encoding='utf-8', object_hook=convert)
+    expected = unpackb(data, raw=False, object_hook=convert)
 
     assert expected == t
 
@@ -53,10 +53,10 @@ def test_tuple_ext():
     def convert(code, payload):
         if code == MSGPACK_EXT_TYPE_TUPLE:
             # Unpack and convert to tuple
-            return tuple(unpackb(payload, encoding='utf-8', ext_hook=convert))
+            return tuple(unpackb(payload, raw=False, ext_hook=convert))
         raise ValueError('Unknown Ext code {}'.format(code))
 
     data = packb(t, strict_types=True, use_bin_type=True, default=default)
-    expected = unpackb(data, encoding='utf-8', ext_hook=convert)
+    expected = unpackb(data, raw=False, ext_hook=convert)
 
     assert expected == t
diff --git a/test/test_unpack.py b/test/test_unpack.py
index c0d711cd77c3123c2ebfbc9eeac8d9fbf1c96fed..00a10612ee72dc314109f4d2c70c9e6c20cb66f4 100644
--- a/test/test_unpack.py
+++ b/test/test_unpack.py
@@ -47,8 +47,8 @@ def test_unpacker_ext_hook():
     class MyUnpacker(Unpacker):
 
         def __init__(self):
-            super(MyUnpacker, self).__init__(ext_hook=self._hook,
-                                             encoding='utf-8')
+            super(MyUnpacker, self).__init__(
+                ext_hook=self._hook, raw=False)
 
         def _hook(self, code, data):
             if code == 1:
@@ -57,11 +57,11 @@ def test_unpacker_ext_hook():
                 return ExtType(code, data)
 
     unpacker = MyUnpacker()
-    unpacker.feed(packb({'a': 1}, encoding='utf-8'))
+    unpacker.feed(packb({'a': 1}))
     assert unpacker.unpack() == {'a': 1}
-    unpacker.feed(packb({'a': ExtType(1, b'123')}, encoding='utf-8'))
+    unpacker.feed(packb({'a': ExtType(1, b'123')}))
     assert unpacker.unpack() == {'a': 123}
-    unpacker.feed(packb({'a': ExtType(2, b'321')}, encoding='utf-8'))
+    unpacker.feed(packb({'a': ExtType(2, b'321')}))
     assert unpacker.unpack() == {'a': ExtType(2, b'321')}