diff --git a/sipsimple/core/_core.util.pxi b/sipsimple/core/_core.util.pxi
index 2c6428d3..08a7435b 100644
--- a/sipsimple/core/_core.util.pxi
+++ b/sipsimple/core/_core.util.pxi
@@ -1,439 +1,439 @@
 
 import platform
 import re
 import sys
 
 from application.version import Version
 
 
 cdef class PJSTR:
     def __cinit__(self, str):
         self.str = str
         _str_to_pj_str(str, &self.pj_str)
 
     def __str__(self):
         return self.str
 
 cdef class SIPStatusMessages:
     cdef object _default_status
 
     def __cinit__(self, *args, **kwargs):
         self._default_status = _pj_str_to_str(pjsip_get_status_text(0)[0])
 
     def __getitem__(self, int val):
         cdef object _status
         _status = _pj_str_to_str(pjsip_get_status_text(val)[0])
         if _status == self._default_status:
             raise IndexError("Unknown SIP response code: %d" % val)
         return _status
 
 
 cdef class frozenlist:
     def __cinit__(self, *args, **kw):
         self.list = list()
         self.initialized = 0
         self.hash = 0
     def __init__(self, *args, **kw):
         if not self.initialized:
             self.list = list(*args, **kw)
             self.initialized = 1
             self.hash = hash(tuple(self.list))
     def __reduce__(self):
         return (self.__class__, (self.list,), None)
     def __repr__(self):
         return "frozenlist(%r)" % self.list
     def __len__(self):
         return self.list.__len__()
     def __hash__(self):
         return self.hash
     def __iter__(self):
         return self.list.__iter__()
     def __cmp__(self, frozenlist other):
         return self.list.__cmp__(other.list)
     def __richcmp__(frozenlist self, other, op):
         if isinstance(other, frozenlist):
             other = (<frozenlist>other).list
         if op == 0:
             return self.list.__cmp__(other) < 0
         elif op == 1:
             return self.list.__cmp__(other) <= 0
         elif op == 2:
             return self.list.__eq__(other)
         elif op == 3:
             return self.list.__ne__(other)
         elif op == 4:
             return self.list.__cmp__(other) > 0
         elif op == 5:
             return self.list.__cmp__(other) >= 0
         else:
             return NotImplemented
     def __contains__(self, item):
         return self.list.__contains__(item)
     def __getitem__(self, key):
         return self.list.__getitem__(key)
     def __add__(first, second):
         if isinstance(first, frozenlist):
             first = (<frozenlist>first).list
         if isinstance(second, frozenlist):
             second = (<frozenlist>second).list
         return frozenlist(first+second)
     def __mul__(first, second):
         if isinstance(first, frozenlist):
             first = (<frozenlist>first).list
         if isinstance(second, frozenlist):
             second = (<frozenlist>second).list
         return frozenlist(first*second)
     def __reversed__(self):
         return self.list.__reversed__()
     def count(self, elem):
         return self.list.count(elem)
     def index(self, elem):
         return self.list.index(elem)
 
 
 cdef class frozendict:
     def __cinit__(self, *args, **kw):
         self.dict = dict()
         self.initialized = 0
     def __init__(self, *args, **kw):
         if not self.initialized:
             self.dict = dict(*args, **kw)
             self.initialized = 1
             self.hash = hash(tuple(self.dict.iteritems()))
     def __reduce__(self):
         return (self.__class__, (self.dict,), None)
     def __repr__(self):
         return "frozendict(%r)" % self.dict
     def __len__(self):
         return self.dict.__len__()
     def __hash__(self):
         return self.hash
     def __iter__(self):
         return self.dict.__iter__()
     def __cmp__(self, frozendict other):
         return self.dict.__cmp__(other.dict)
     def __richcmp__(frozendict self, other, op):
         if isinstance(other, frozendict):
             other = (<frozendict>other).dict
         if op == 0:
             return self.dict.__cmp__(other) < 0
         elif op == 1:
             return self.dict.__cmp__(other) <= 0
         elif op == 2:
             return self.dict.__eq__(other)
         elif op == 3:
             return self.dict.__ne__(other)
         elif op == 4:
             return self.dict.__cmp__(other) > 0
         elif op == 5:
             return self.dict.__cmp__(other) >= 0
         else:
             return NotImplemented
     def __contains__(self, item):
         return self.dict.__contains__(item)
     def __getitem__(self, key):
         return self.dict.__getitem__(key)
     def copy(self):
         return self
     def get(self, *args):
         return self.dict.get(*args)
     def has_key(self, key):
         return self.dict.has_key(key)
     def items(self):
         return list(self.dict.items())
     def iteritems(self):
         return list(self.dict.items())
     def iterkeys(self):
         return list(self.dict.keys())
     def itervalues(self):
         return list(self.dict.values())
     def keys(self):
         return list(self.dict.keys())
     def values(self):
         return list(self.dict.values())
 
 
 # functions
 
 cdef int _str_to_pj_str(object string, pj_str_t *pj_str) except -1:
     if type(string) != bytes:
         pj_str.ptr = PyBytes_AsString(string.encode())
     else:
         pj_str.ptr = PyBytes_AsString(string)
     pj_str.slen = len(string)
 
 cdef object _pj_str_to_bytes(pj_str_t pj_str):
     return PyBytes_FromStringAndSize(pj_str.ptr, pj_str.slen)
 
 cdef object _pj_str_to_str(pj_str_t pj_str):
     return PyBytes_FromStringAndSize(pj_str.ptr, pj_str.slen).decode()
 
 cdef object _pj_buf_len_to_str(object buf, int buf_len):
     return PyBytes_FromStringAndSize(buf, buf_len)
 
 cdef object _buf_to_str(object buf):
     return PyBytes_FromString(buf).decode()
 
 cdef object _str_as_str(object string):
     if type(string) != bytes:
         return PyBytes_AsString(string.encode())
     else:
         return PyBytes_AsString(string)
 
 cdef object _str_as_size(object string):
     if type(string) != bytes:
         return PyBytes_Size(string.encode())
     else:
         return PyBytes_Size(string)
 
 cdef object _pj_status_to_str(int status):
     cdef char buf[PJ_ERR_MSG_SIZE]
     return _pj_str_to_str(pj_strerror(status, buf, PJ_ERR_MSG_SIZE))
 
 cdef object _pj_status_to_def(int status):
     return _re_pj_status_str_def.match(_pj_status_to_str(status)).group(1)
 
 cdef dict _pjsip_param_to_dict(pjsip_param *param_list):
     cdef pjsip_param *param
     cdef dict retval = dict()
     param = <pjsip_param *> (<pj_list *> param_list).next
     while param != param_list:
         if param.value.slen == 0:
             retval[_pj_str_to_str(param.name)] = None
         else:
             retval[_pj_str_to_str(param.name)] = _pj_str_to_str(param.value)
         param = <pjsip_param *> (<pj_list *> param).next
     return retval
 
 cdef int _dict_to_pjsip_param(object params, pjsip_param *param_list, pj_pool_t *pool):
     cdef pjsip_param *param = NULL
     for name, value in params.iteritems():
         param = <pjsip_param *> pj_pool_alloc(pool, sizeof(pjsip_param))
         if param == NULL:
             return -1
         name = name if isinstance(name, bytes) else name.encode()
         _str_to_pj_str(name, &param.name)
         if value is None:
             param.value.slen = 0
         else:
             value = value if isinstance(value, bytes) else value.encode()
             _str_to_pj_str(value, &param.value)
         pj_list_insert_after(<pj_list *> param_list, <pj_list *> param)
     return 0
 
 cdef int _pjsip_msg_to_dict(pjsip_msg *msg, dict info_dict) except -1:
     cdef pjsip_msg_body *body
     cdef pjsip_hdr *header
     cdef pjsip_generic_array_hdr *array_header
     cdef pjsip_ctype_hdr *ctype_header
     cdef pjsip_cseq_hdr *cseq_header
     cdef char *buf
     cdef int buf_len, status
     headers = {}
     header = <pjsip_hdr *> (<pj_list *> &msg.hdr).next
     while header != &msg.hdr:
         header_name = _pj_str_to_str(header.name)
         header_data = None
         multi_header = False
         if header_name in ("Accept", "Allow", "Require", "Supported", "Unsupported", "Allow-Events"):
             array_header = <pjsip_generic_array_hdr *> header
             header_data = []
             if array_header.count < 128:
                 for i from 0 <= i < array_header.count:
                     header_data.append(_pj_str_to_bytes(array_header.values[i]))
         elif header_name == "Contact":
             multi_header = True
             header_data = FrozenContactHeader_create(<pjsip_contact_hdr *> header)
         elif header_name == "Content-Length":
             header_data = (<pjsip_clen_hdr *> header).len
         elif header_name == "Content-Type":
             header_data = FrozenContentTypeHeader_create(<pjsip_ctype_hdr *> header)
         elif header_name == "CSeq":
             cseq_header = <pjsip_cseq_hdr *> header
             hvalue = _pj_str_to_str(cseq_header.method.name)
             header_data = (cseq_header.cseq, hvalue)
         elif header_name in ("Expires", "Max-Forwards", "Min-Expires"):
             header_data = (<pjsip_generic_int_hdr *> header).ivalue
         elif header_name == "From":
             header_data = FrozenFromHeader_create(<pjsip_fromto_hdr *> header)
         elif header_name == "To":
             header_data = FrozenToHeader_create(<pjsip_fromto_hdr *> header)
         elif header_name == "Route":
             multi_header = True
             header_data = FrozenRouteHeader_create(<pjsip_routing_hdr *> header)
         elif header_name == "Reason":
             value = _pj_str_to_str((<pjsip_generic_string_hdr *>header).hvalue)
             protocol, sep, params_str = value.partition(';')
             params = frozendict([(name, value or None) for name, sep, value in [param.partition('=') for param in params_str.split(';')]])
             header_data = FrozenReasonHeader(protocol, params)
         elif header_name == "Record-Route":
             multi_header = True
             header_data = FrozenRecordRouteHeader_create(<pjsip_routing_hdr *> header)
         elif header_name == "Retry-After":
             header_data = FrozenRetryAfterHeader_create(<pjsip_retry_after_hdr *> header)
         elif header_name == "Via":
             multi_header = True
             header_data = FrozenViaHeader_create(<pjsip_via_hdr *> header)
         elif header_name == "Warning":
             match = _re_warning_hdr.match(_pj_str_to_str((<pjsip_generic_string_hdr *>header).hvalue))
             if match is not None:
                 warning_params = match.groupdict()
                 warning_params['code'] = int(warning_params['code'])
                 header_data = FrozenWarningHeader(**warning_params)
         elif header_name == "Event":
             header_data = FrozenEventHeader_create(<pjsip_event_hdr *> header)
         elif header_name == "Subscription-State":
             header_data = FrozenSubscriptionStateHeader_create(<pjsip_sub_state_hdr *> header)
         elif header_name == "Refer-To":
             header_data = FrozenReferToHeader_create(<pjsip_generic_string_hdr *> header)
         elif header_name == "Subject":
             header_data = FrozenSubjectHeader_create(<pjsip_generic_string_hdr *> header)
         elif header_name == "Replaces":
             header_data = FrozenReplacesHeader_create(<pjsip_replaces_hdr *> header)
         # skip the following headers:
         elif header_name not in ("Authorization", "Proxy-Authenticate", "Proxy-Authorization", "WWW-Authenticate"):
             hvalue = (<pjsip_generic_string_hdr *> header).hvalue
             header_value = _pj_str_to_str(hvalue)
             header_data = FrozenHeader(header_name, header_value)
 
         if header_data is not None:
             if multi_header:
                 headers.setdefault(header_name, []).append(header_data)
             else:
                 if header_name not in headers:
                     headers[header_name] = header_data
         header = <pjsip_hdr *> (<pj_list *> header).next
     info_dict["headers"] = headers
     body = msg.body
 
     if body == NULL:
         info_dict["body"] = None
     else:
         status = pjsip_print_body(body, &buf, &buf_len)
         if status != 0:
             info_dict["body"] = None
         else:
             info_dict["body"] = _pj_buf_len_to_str(buf, buf_len)
 
     if msg.type == PJSIP_REQUEST_MSG:
         info_dict["method"] = _pj_str_to_str(msg.line.req.method.name)
         # You need to call pjsip_uri_get_uri on the request URI if the message is for transmitting,
         # but it isn't required if message is one received. Otherwise, a seg fault occurs. Don't ask.
         info_dict["request_uri"] = FrozenSIPURI_create(<pjsip_sip_uri*>pjsip_uri_get_uri(msg.line.req.uri))
     else:
         info_dict["code"] = msg.line.status.code
         info_dict["reason"] = _pj_str_to_str(msg.line.status.reason)
     return 0
 
 cdef int _is_valid_ip(int af, object ip) except -1:
     cdef char buf[16]
     cdef pj_str_t src
     cdef int status
     _str_to_pj_str(ip, &src)
     status = pj_inet_pton(af, &src, buf)
     if status == 0:
         return 1
     else:
         return 0
 
 cdef int _get_ip_version(object ip) except -1:
     if _is_valid_ip(pj_AF_INET(), ip):
         return pj_AF_INET()
     elif _is_valid_ip(pj_AF_INET6(), ip):
         return pj_AF_INET()
     else:
         return 0
 
 cdef int _add_headers_to_tdata(pjsip_tx_data *tdata, object headers) except -1:
     cdef pj_str_t name_pj, value_pj
     cdef pjsip_hdr *hdr
     for header in headers:
-        hb = header.name.decode() if isinstance(header.name, bytes) else header.name
-        bb = header.body.decode() if isinstance(header.body, bytes) else header.body
+        hb = header.name if isinstance(header.name, bytes) else header.name.encode()
+        bb = header.body if isinstance(header.body, bytes) else header.body.encode()
         _str_to_pj_str(hb, &name_pj)
         _str_to_pj_str(bb, &value_pj)
         hdr = <pjsip_hdr *> pjsip_generic_string_hdr_create(tdata.pool, &name_pj, &value_pj)
         pjsip_msg_add_hdr(tdata.msg, hdr)
 
 cdef int _remove_headers_from_tdata(pjsip_tx_data *tdata, object headers) except -1:
     cdef pj_str_t header_name_pj
     cdef pjsip_hdr *hdr
     for header in headers:
         _str_to_pj_str(header, &header_name_pj)
         hdr = <pjsip_hdr *> pjsip_msg_find_remove_hdr_by_name(tdata.msg, &header_name_pj, NULL)
 
 cdef int _BaseRouteHeader_to_pjsip_route_hdr(BaseIdentityHeader header, pjsip_route_hdr *pj_header, pj_pool_t *pool) except -1:
     cdef pjsip_param *param
     cdef pjsip_sip_uri *sip_uri
     pjsip_route_hdr_init(NULL, <void *> pj_header)
     sip_uri = <pjsip_sip_uri *> pj_pool_alloc(pool, sizeof(pjsip_sip_uri))
     _BaseSIPURI_to_pjsip_sip_uri(header.uri, sip_uri, pool)
     
     pj_header.name_addr.uri = <pjsip_uri *> sip_uri
     if header.display_name:
         _str_to_pj_str(header.display_name, &pj_header.name_addr.display)
     _dict_to_pjsip_param(header.parameters, &pj_header.other_param, pool)
     return 0
 
 cdef int _BaseSIPURI_to_pjsip_sip_uri(BaseSIPURI uri, pjsip_sip_uri *pj_uri, pj_pool_t *pool) except -1:
     cdef pjsip_param *param
     pjsip_sip_uri_init(pj_uri, uri.secure)
     if uri.user:
         _str_to_pj_str(uri.user, &pj_uri.user)
     if uri.password:
         _str_to_pj_str(uri.password, &pj_uri.passwd)
     if uri.host:
         _str_to_pj_str(uri.host, &pj_uri.host)
     if uri.port:
         pj_uri.port = uri.port
 
     for name, value in uri.parameters.iteritems():
         if name == "lr":
             pj_uri.lr_param = 1
         elif name == "maddr":
             _str_to_pj_str(value, &pj_uri.maddr_param)
         elif name == "method":
             _str_to_pj_str(value, &pj_uri.method_param)
         elif name == "transport":
             _str_to_pj_str(value, &pj_uri.transport_param)
         elif name == "ttl":
             pj_uri.ttl_param = int(value)
         elif name == "user":
             _str_to_pj_str(value, &pj_uri.user_param)
         else:
             param = <pjsip_param *> pj_pool_alloc(pool, sizeof(pjsip_param))
             if name == 'hide':
                 name = b'hide'
             elif name == 'tls_name':
                 name = b'tls_name'
             _str_to_pj_str(name, &param.name)
             if value is None:
                 param.value.slen = 0
             else:
                 _str_to_pj_str(value, &param.value)
             pj_list_insert_after(<pj_list *> &pj_uri.other_param, <pj_list *> param)
     _dict_to_pjsip_param(uri.headers, &pj_uri.header_param, pool)
     return 0
 
 
 def _get_device_name_encoding():
     if sys.platform == 'win32':
         encoding = 'mbcs'
     elif sys.platform.startswith('linux2') and Version.parse(platform.release()) < Version(2,6,31):
         encoding = 'latin1'
     else:
         encoding = 'utf-8'
     return encoding
 _device_name_encoding = _get_device_name_encoding()
 
 def decode_device_name(device_name):
     # ignore decoding errors, some systems (I'm looking at you, OSX), seem to misbehave
     return device_name.decode(_device_name_encoding, 'ignore')
 
 
 # globals
 
 cdef object _re_pj_status_str_def = re.compile("^.*\((.*)\)$")
 cdef object _re_warning_hdr = re.compile('(?P<code>[0-9]{3}) (?P<agent>.*?) "(?P<text>.*?)"')
 sip_status_messages = SIPStatusMessages()