diff --git a/src/calibre/devices/mtp/unix/libmtp.c b/src/calibre/devices/mtp/unix/libmtp.c
index 8d8481d551..6456ec4afd 100644
--- a/src/calibre/devices/mtp/unix/libmtp.c
+++ b/src/calibre/devices/mtp/unix/libmtp.c
@@ -86,7 +86,11 @@ static uint16_t data_to_python(void *params, void *priv, uint32_t sendlen, unsig
     cb = (ProgressCallback *)priv;
     *putlen = sendlen;
     PyEval_RestoreThread(cb->state);
+#if PY_MAJOR_VERSION >= 3
+    res = PyObject_CallMethod(cb->extra, "write", "y#", data, (Py_ssize_t)sendlen);
+#else
     res = PyObject_CallMethod(cb->extra, "write", "s#", data, (Py_ssize_t)sendlen);
+#endif
     if (res == NULL) {
         ret = LIBMTP_HANDLER_RETURN_ERROR;
         *putlen = 0;
@@ -608,45 +612,44 @@ static PyGetSetDef Device_getsetters[] = {
 };
 
 static PyTypeObject DeviceType = { // {{{
-    PyObject_HEAD_INIT(NULL)
-    0,                         /*ob_size*/
-    "libmtp.Device",            /*tp_name*/
-    sizeof(Device),      /*tp_basicsize*/
-    0,                         /*tp_itemsize*/
-    (destructor)Device_dealloc, /*tp_dealloc*/
-    0,                         /*tp_print*/
-    0,                         /*tp_getattr*/
-    0,                         /*tp_setattr*/
-    0,                         /*tp_compare*/
-    0,                         /*tp_repr*/
-    0,                         /*tp_as_number*/
-    0,                         /*tp_as_sequence*/
-    0,                         /*tp_as_mapping*/
-    0,                         /*tp_hash */
-    0,                         /*tp_call*/
-    0,                         /*tp_str*/
-    0,                         /*tp_getattro*/
-    0,                         /*tp_setattro*/
-    0,                         /*tp_as_buffer*/
-    Py_TPFLAGS_DEFAULT|Py_TPFLAGS_BASETYPE,        /*tp_flags*/
-    "Device",                  /* tp_doc */
-    0,		               /* tp_traverse */
-    0,		               /* tp_clear */
-    0,		               /* tp_richcompare */
-    0,		               /* tp_weaklistoffset */
-    0,		               /* tp_iter */
-    0,		               /* tp_iternext */
-    Device_methods,             /* tp_methods */
-    0,             /* tp_members */
-    Device_getsetters,                         /* tp_getset */
-    0,                         /* tp_base */
-    0,                         /* tp_dict */
-    0,                         /* tp_descr_get */
-    0,                         /* tp_descr_set */
-    0,                         /* tp_dictoffset */
-    (initproc)Device_init,      /* tp_init */
-    0,                         /* tp_alloc */
-    0,                 /* tp_new */
+    PyVarObject_HEAD_INIT(NULL, 0)
+    /* tp_name             */ "libmtp.Device",
+    /* tp_basicsize        */ sizeof(Device),
+    /* tp_itemsize         */ 0,
+    /* tp_dealloc          */ (destructor)Device_dealloc,
+    /* tp_print            */ 0,
+    /* tp_getattr          */ 0,
+    /* tp_setattr          */ 0,
+    /* tp_compare          */ 0,
+    /* tp_repr             */ 0,
+    /* tp_as_number        */ 0,
+    /* tp_as_sequence      */ 0,
+    /* tp_as_mapping       */ 0,
+    /* tp_hash             */ 0,
+    /* tp_call             */ 0,
+    /* tp_str              */ 0,
+    /* tp_getattro         */ 0,
+    /* tp_setattro         */ 0,
+    /* tp_as_buffer        */ 0,
+    /* tp_flags            */ Py_TPFLAGS_DEFAULT|Py_TPFLAGS_BASETYPE,
+    /* tp_doc              */ "Device",
+    /* tp_traverse         */ 0,
+    /* tp_clear            */ 0,
+    /* tp_richcompare      */ 0,
+    /* tp_weaklistoffset   */ 0,
+    /* tp_iter             */ 0,
+    /* tp_iternext         */ 0,
+    /* tp_methods          */ Device_methods,
+    /* tp_members          */ 0,
+    /* tp_getset           */ Device_getsetters,
+    /* tp_base             */ 0,
+    /* tp_dict             */ 0,
+    /* tp_descr_get        */ 0,
+    /* tp_descr_set        */ 0,
+    /* tp_dictoffset       */ 0,
+    /* tp_init             */ (initproc)Device_init,
+    /* tp_alloc            */ 0,
+    /* tp_new              */ 0,
 }; // }}}
 
 // }}} End Device object definition
@@ -695,6 +698,8 @@ known_devices(PyObject *self, PyObject *args) {
     return ans;
 }
 
+static char libmtp_doc[] = "Interface to libmtp.";
+
 static PyMethodDef libmtp_methods[] = {
     {"set_debug_level", set_debug_level, METH_VARARGS,
         "set_debug_level(level)\n\nSet the debug level bit mask, see LIBMTP_DEBUG_* constants."
@@ -712,19 +717,41 @@ static PyMethodDef libmtp_methods[] = {
 };
 
 
-CALIBRE_MODINIT_FUNC
-initlibmtp(void) {
-    PyObject *m;
+#if PY_MAJOR_VERSION >= 3
+#define INITERROR return NULL
+#define INITMODULE PyModule_Create(&libmtp_module)
+static struct PyModuleDef libmtp_module = {
+    /* m_base     */ PyModuleDef_HEAD_INIT,
+    /* m_name     */ "libmtp",
+    /* m_doc      */ libmtp_doc,
+    /* m_size     */ -1,
+    /* m_methods  */ libmtp_methods,
+    /* m_slots    */ 0,
+    /* m_traverse */ 0,
+    /* m_clear    */ 0,
+    /* m_free     */ 0,
+};
+CALIBRE_MODINIT_FUNC PyInit_libmtp(void) {
+#else
+#define INITERROR return
+#define INITMODULE Py_InitModule3("libmtp", libmtp_methods, libmtp_doc);
+CALIBRE_MODINIT_FUNC initlibmtp(void) {
+#endif
 
     DeviceType.tp_new = PyType_GenericNew;
-    if (PyType_Ready(&DeviceType) < 0)
-        return;
+    if (PyType_Ready(&DeviceType) < 0) {
+        INITERROR;
+    }
 
-    m = Py_InitModule3("libmtp", libmtp_methods, "Interface to libmtp.");
-    if (m == NULL) return;
+    PyObject *m = INITMODULE;
+    if (m == NULL) {
+        INITERROR;
+    }
 
     MTPError = PyErr_NewException("libmtp.MTPError", NULL, NULL);
-    if (MTPError == NULL) return;
+    if (MTPError == NULL) {
+        INITERROR;
+    }
     PyModule_AddObject(m, "MTPError", MTPError);
 
     // Redirect stdout to get rid of the annoying message about mtpz. Really,
@@ -754,4 +781,8 @@ initlibmtp(void) {
     PyModule_AddIntMacro(m, LIBMTP_DEBUG_USB);
     PyModule_AddIntMacro(m, LIBMTP_DEBUG_DATA);
     PyModule_AddIntMacro(m, LIBMTP_DEBUG_ALL);
+
+#if PY_MAJOR_VERSION >= 3
+    return m;
+#endif
 }
diff --git a/src/calibre/devices/mtp/unix/upstream/update.py b/src/calibre/devices/mtp/unix/upstream/update.py
old mode 100644
new mode 100755
index 0fc6a2b41c..98edf95812
--- a/src/calibre/devices/mtp/unix/upstream/update.py
+++ b/src/calibre/devices/mtp/unix/upstream/update.py
@@ -1,4 +1,4 @@
-#!/usr/bin/env python2
+#!/usr/bin/env python3
 # vim:fileencoding=UTF-8:ts=4:sw=4:sta:et:sts=4:fdm=marker:ai
 from __future__ import (unicode_literals, division, absolute_import,
                         print_function)
@@ -14,9 +14,7 @@ base = os.path.dirname(os.path.abspath(__file__))
 os.chdir('/tmp')
 if os.path.exists('libmtp'):
     shutil.rmtree('libmtp')
-subprocess.check_call(['git', 'clone', 'git://git.code.sf.net/p/libmtp/code',
+subprocess.check_call(['git', 'clone', '--depth=1', 'git://git.code.sf.net/p/libmtp/code',
                        'libmtp'])
 for x in ('src/music-players.h', 'src/device-flags.h'):
-    with open(os.path.join(base, os.path.basename(x)), 'wb') as f:
-        shutil.copyfileobj(open('libmtp/'+x), f)
-
+    shutil.copyfile('libmtp/'+x, os.path.join(base, os.path.basename(x)))
diff --git a/src/calibre/devices/mtp/windows/content_enumeration.cpp b/src/calibre/devices/mtp/windows/content_enumeration.cpp
index 67fe2b7914..9afff2461d 100644
--- a/src/calibre/devices/mtp/windows/content_enumeration.cpp
+++ b/src/calibre/devices/mtp/windows/content_enumeration.cpp
@@ -554,7 +554,11 @@ PyObject* wpd::get_file(IPortableDevice *device, const wchar_t *object_id, PyObj
             PyErr_SetString(PyExc_IOError, "Read access is denied to this object"); break;
         } else if (SUCCEEDED(hr)) {
             if (bytes_read > 0) {
+#if PY_MAJOR_VERSION >= 3
+                res = PyObject_CallMethod(dest, "write", "y#", buf, bytes_read);
+#else
                 res = PyObject_CallMethod(dest, "write", "s#", buf, bytes_read);
+#endif
                 if (res == NULL) break;
                 Py_DECREF(res); res = NULL;
                 if (callback != NULL) Py_XDECREF(PyObject_CallFunction(callback, "kK", total_read, filesize));
diff --git a/src/calibre/ebooks/compression/palmdoc.c b/src/calibre/ebooks/compression/palmdoc.c
index 61d00ab04f..623bb10f67 100644
--- a/src/calibre/ebooks/compression/palmdoc.c
+++ b/src/calibre/ebooks/compression/palmdoc.c
@@ -42,12 +42,20 @@ typedef struct {
 
 #define CHAR(x) (( (x) > 127 ) ? (x)-256 : (x))
 
+#if PY_MAJOR_VERSION >= 3
+    #define BUFFER_FMT "y*"
+    #define BYTES_FMT "y#"
+#else
+    #define BUFFER_FMT "t#"
+    #define BYTES_FMT "s#"
+#endif
+
 static PyObject *
 cpalmdoc_decompress(PyObject *self, PyObject *args) {
     const char *_input = NULL; Py_ssize_t input_len = 0;
     Byte *input; char *output; Byte c; PyObject *ans;
     Py_ssize_t i = 0, o = 0, j = 0, di, n;
-    if (!PyArg_ParseTuple(args, "t#", &_input, &input_len))
+    if (!PyArg_ParseTuple(args, BUFFER_FMT, &_input, &input_len))
 		return NULL;
     input = (Byte *) PyMem_Malloc(sizeof(Byte)*input_len);
     if (input == NULL) return PyErr_NoMemory();
@@ -76,7 +84,7 @@ cpalmdoc_decompress(PyObject *self, PyObject *args) {
                 output[o] = output[o - di];
         }
     }
-    ans = Py_BuildValue("s#", output, o);
+    ans = Py_BuildValue(BYTES_FMT, output, o);
     if (output != NULL) PyMem_Free(output);
     if (input != NULL) PyMem_Free(input);
     return ans;
@@ -162,7 +170,7 @@ cpalmdoc_compress(PyObject *self, PyObject *args) {
     char *output; PyObject *ans;
     Py_ssize_t j = 0;
     buffer b;
-    if (!PyArg_ParseTuple(args, "t#", &_input, &input_len))
+    if (!PyArg_ParseTuple(args, BUFFER_FMT, &_input, &input_len))
 		return NULL;
     b.data = (Byte *)PyMem_Malloc(sizeof(Byte)*input_len);
     if (b.data == NULL) return PyErr_NoMemory();
@@ -176,7 +184,7 @@ cpalmdoc_compress(PyObject *self, PyObject *args) {
     if (output == NULL) return PyErr_NoMemory();
     j = cpalmdoc_do_compress(&b, output);
     if ( j == 0) return PyErr_NoMemory();
-    ans = Py_BuildValue("s#", output, j);
+    ans = Py_BuildValue(BYTES_FMT, output, j);
     PyMem_Free(output);
     PyMem_Free(b.data);
     return ans;
@@ -203,4 +211,3 @@ initcPalmdoc(void) {
     );
     if (m == NULL) return;
 }
-
diff --git a/src/calibre/utils/fonts/winfonts.cpp b/src/calibre/utils/fonts/winfonts.cpp
index 428f31d529..bafc8b5728 100644
--- a/src/calibre/utils/fonts/winfonts.cpp
+++ b/src/calibre/utils/fonts/winfonts.cpp
@@ -165,7 +165,11 @@ static PyObject* add_font(PyObject *self, PyObject *args) {
     Py_ssize_t sz;
     DWORD num = 0;
 
+#if PY_MAJOR_VERSION >= 3
+    if (!PyArg_ParseTuple(args, "y#", &data, &sz)) return NULL;
+#else
     if (!PyArg_ParseTuple(args, "s#", &data, &sz)) return NULL;
+#endif
 
     AddFontMemResourceEx(data, (DWORD)sz, NULL, &num);
 
@@ -260,4 +264,3 @@ initwinfonts(void) {
     PyModule_AddIntMacro(m, FW_HEAVY);
     PyModule_AddIntMacro(m, FW_BLACK);
 }
-
diff --git a/src/calibre/utils/lzx/compressor.c b/src/calibre/utils/lzx/compressor.c
index b63ee3ee95..605ca515f5 100644
--- a/src/calibre/utils/lzx/compressor.c
+++ b/src/calibre/utils/lzx/compressor.c
@@ -310,7 +310,11 @@ Compressor_compress(Compressor *self, PyObject *args, PyObject *kwds)
     int flush = 0;
 
     if (!PyArg_ParseTupleAndKeywords(
+#if PYTHON_MAJOR_VERSION >= 3
+            args, kwds, "y#|b", kwlist, &data, &inlen, &flush)) {
+#else
             args, kwds, "s#|b", kwlist, &data, &inlen, &flush)) {
+#endif
         return NULL;
     }
 
diff --git a/src/calibre/utils/lzx/lzxmodule.c b/src/calibre/utils/lzx/lzxmodule.c
index 6c9a4f15d8..3cb5d36919 100644
--- a/src/calibre/utils/lzx/lzxmodule.c
+++ b/src/calibre/utils/lzx/lzxmodule.c
@@ -157,7 +157,11 @@ decompress(PyObject *self, PyObject *args)
     memory_file dest;
     PyObject *retval = NULL;
 
+#if PY_MAJOR_VERSION >= 3
+    if (!PyArg_ParseTuple(args, "y#I", &inbuf, &inlen, &outlen)) {
+#else
     if (!PyArg_ParseTuple(args, "s#I", &inbuf, &inlen, &outlen)) {
+#endif
         return NULL;
     }
 
diff --git a/src/calibre/utils/podofo/doc.cpp b/src/calibre/utils/podofo/doc.cpp
index 6e73e729bd..9f19b47446 100644
--- a/src/calibre/utils/podofo/doc.cpp
+++ b/src/calibre/utils/podofo/doc.cpp
@@ -32,12 +32,18 @@ PDFDoc_new(PyTypeObject *type, PyObject *args, PyObject *kwds)
 }
 // }}}
 
+#if PY_MAJOR_VERSION >= 3
+    #define BYTES_FMT "y#"
+#else
+    #define BYTES_FMT "s#"
+#endif
+
 // Loading/Opening of PDF files {{{
 static PyObject *
 PDFDoc_load(PDFDoc *self, PyObject *args) {
     char *buffer; Py_ssize_t size;
 
-    if (PyArg_ParseTuple(args, "s#", &buffer, &size)) {
+    if (PyArg_ParseTuple(args, BYTES_FMT, &buffer, &size)) {
         try {
 #if PODOFO_VERSION <= 0x000905
             self->doc->Load(buffer, (long)size);
@@ -77,7 +83,7 @@ static PyObject *
 PDFDoc_save(PDFDoc *self, PyObject *args) {
     char *buffer;
 
-    if (PyArg_ParseTuple(args, "s", &buffer)) {
+    if (PyArg_ParseTuple(args, BYTES_FMT, &buffer)) {
         try {
             self->doc->Write(buffer);
         } catch(const PdfError & err) {
@@ -284,7 +290,7 @@ PDFDoc_get_xmp_metadata(PDFDoc *self, PyObject *args) {
             if ((str = metadata->GetStream()) != NULL) {
                 str->GetFilteredCopy(&buf, &len);
                 if (buf != NULL) {
-                    ans = Py_BuildValue("s#", buf, len);
+                    ans = Py_BuildValue(BYTES_FMT, buf, len);
                     free(buf); buf = NULL;
                     if (ans == NULL) goto error;
                 }
@@ -312,7 +318,7 @@ PDFDoc_set_xmp_metadata(PDFDoc *self, PyObject *args) {
     TVecFilters compressed(1);
     compressed[0] = ePdfFilter_FlateDecode;
 
-    if (!PyArg_ParseTuple(args, "s#", &raw, &len)) return NULL;
+    if (!PyArg_ParseTuple(args, BYTES_FMT, &raw, &len)) return NULL;
     try {
         if ((metadata = self->doc->GetMetadata()) != NULL) {
             if ((str = metadata->GetStream()) == NULL) { PyErr_NoMemory(); goto error; }
@@ -343,7 +349,11 @@ error:
 static PyObject *
 PDFDoc_pages_getter(PDFDoc *self, void *closure) {
     int pages = self->doc->GetPageCount();
+#if PY_MAJOR_VERSION >= 3
+    PyObject *ans = PyLong_FromLong(static_cast<long>(pages));
+#else
     PyObject *ans = PyInt_FromLong(static_cast<long>(pages));
+#endif
     if (ans != NULL) Py_INCREF(ans);
     return ans;
 }
@@ -595,45 +605,43 @@ static PyMethodDef PDFDoc_methods[] = {
 
 // Type definition {{{
 PyTypeObject pdf::PDFDocType = {
-    PyObject_HEAD_INIT(NULL)
-    0,                         /*ob_size*/
-    "podofo.PDFDoc",             /*tp_name*/
-    sizeof(PDFDoc), /*tp_basicsize*/
-    0,                         /*tp_itemsize*/
-    (destructor)PDFDoc_dealloc,                         /*tp_dealloc*/
-    0,                         /*tp_print*/
-    0,                         /*tp_getattr*/
-    0,                         /*tp_setattr*/
-    0,                         /*tp_compare*/
-    0,                         /*tp_repr*/
-    0,                         /*tp_as_number*/
-    0,                         /*tp_as_sequence*/
-    0,                         /*tp_as_mapping*/
-    0,                         /*tp_hash */
-    0,                         /*tp_call*/
-    0,                         /*tp_str*/
-    0,                         /*tp_getattro*/
-    0,                         /*tp_setattro*/
-    0,                         /*tp_as_buffer*/
-    Py_TPFLAGS_DEFAULT,        /*tp_flags*/
-    "PDF Documents",           /* tp_doc */
-    0,		               /* tp_traverse */
-    0,		               /* tp_clear */
-    0,		               /* tp_richcompare */
-    0,		               /* tp_weaklistoffset */
-    0,		               /* tp_iter */
-    0,		               /* tp_iternext */
-    PDFDoc_methods,             /* tp_methods */
-    0,             /* tp_members */
-    PDFDoc_getsetters,                         /* tp_getset */
-    0,                         /* tp_base */
-    0,                         /* tp_dict */
-    0,                         /* tp_descr_get */
-    0,                         /* tp_descr_set */
-    0,                         /* tp_dictoffset */
-    0,      /* tp_init */
-    0,                         /* tp_alloc */
-    PDFDoc_new,                 /* tp_new */
-
+    PyVarObject_HEAD_INIT(NULL, 0)
+    /* tp_name           */ "podofo.PDFDoc",
+    /* tp_basicsize      */ sizeof(PDFDoc),
+    /* tp_itemsize       */ 0,
+    /* tp_dealloc        */ (destructor)PDFDoc_dealloc,
+    /* tp_print          */ 0,
+    /* tp_getattr        */ 0,
+    /* tp_setattr        */ 0,
+    /* tp_compare        */ 0,
+    /* tp_repr           */ 0,
+    /* tp_as_number      */ 0,
+    /* tp_as_sequence    */ 0,
+    /* tp_as_mapping     */ 0,
+    /* tp_hash           */ 0,
+    /* tp_call           */ 0,
+    /* tp_str            */ 0,
+    /* tp_getattro       */ 0,
+    /* tp_setattro       */ 0,
+    /* tp_as_buffer      */ 0,
+    /* tp_flags          */ Py_TPFLAGS_DEFAULT,
+    /* tp_doc            */ "PDF Documents",
+    /* tp_traverse       */ 0,
+    /* tp_clear          */ 0,
+    /* tp_richcompare    */ 0,
+    /* tp_weaklistoffset */ 0,
+    /* tp_iter           */ 0,
+    /* tp_iternext       */ 0,
+    /* tp_methods        */ PDFDoc_methods,
+    /* tp_members        */ 0,
+    /* tp_getset         */ PDFDoc_getsetters,
+    /* tp_base           */ 0,
+    /* tp_dict           */ 0,
+    /* tp_descr_get      */ 0,
+    /* tp_descr_set      */ 0,
+    /* tp_dictoffset     */ 0,
+    /* tp_init           */ 0,
+    /* tp_alloc          */ 0,
+    /* tp_new            */ PDFDoc_new,
 };
 // }}}
diff --git a/src/calibre/utils/podofo/outline.cpp b/src/calibre/utils/podofo/outline.cpp
index b7be4aeae8..01a3b186d9 100644
--- a/src/calibre/utils/podofo/outline.cpp
+++ b/src/calibre/utils/podofo/outline.cpp
@@ -96,45 +96,43 @@ static PyMethodDef methods[] = {
 
 // Type definition {{{
 PyTypeObject pdf::PDFOutlineItemType = {
-    PyObject_HEAD_INIT(NULL)
-    0,                         /*ob_size*/
-    "podofo.PDFOutlineItem",   /*tp_name*/
-    sizeof(PDFOutlineItem),    /*tp_basicsize*/
-    0,                         /*tp_itemsize*/
-    (destructor)dealloc,       /*tp_dealloc*/
-    0,                         /*tp_print*/
-    0,                         /*tp_getattr*/
-    0,                         /*tp_setattr*/
-    0,                         /*tp_compare*/
-    0,                         /*tp_repr*/
-    0,                         /*tp_as_number*/
-    0,                         /*tp_as_sequence*/
-    0,                         /*tp_as_mapping*/
-    0,                         /*tp_hash */
-    0,                         /*tp_call*/
-    0,                         /*tp_str*/
-    0,                         /*tp_getattro*/
-    0,                         /*tp_setattro*/
-    0,                         /*tp_as_buffer*/
-    Py_TPFLAGS_DEFAULT,        /*tp_flags*/
-    "PDF Outline items",       /* tp_doc */
-    0,		               /* tp_traverse */
-    0,		               /* tp_clear */
-    0,		               /* tp_richcompare */
-    0,		               /* tp_weaklistoffset */
-    0,		               /* tp_iter */
-    0,		               /* tp_iternext */
-    methods,             /* tp_methods */
-    0,             /* tp_members */
-    0,                         /* tp_getset */
-    0,                         /* tp_base */
-    0,                         /* tp_dict */
-    0,                         /* tp_descr_get */
-    0,                         /* tp_descr_set */
-    0,                         /* tp_dictoffset */
-    0,      /* tp_init */
-    0,                         /* tp_alloc */
-    new_item,                 /* tp_new */
-
+    PyVarObject_HEAD_INIT(NULL, 0)
+    /* tp_name           */ "podofo.PDFOutlineItem",
+    /* tp_basicsize      */ sizeof(PDFOutlineItem),
+    /* tp_itemsize       */ 0,
+    /* tp_dealloc        */ (destructor)dealloc,
+    /* tp_print          */ 0,
+    /* tp_getattr        */ 0,
+    /* tp_setattr        */ 0,
+    /* tp_compare        */ 0,
+    /* tp_repr           */ 0,
+    /* tp_as_number      */ 0,
+    /* tp_as_sequence    */ 0,
+    /* tp_as_mapping     */ 0,
+    /* tp_hash           */ 0,
+    /* tp_call           */ 0,
+    /* tp_str            */ 0,
+    /* tp_getattro       */ 0,
+    /* tp_setattro       */ 0,
+    /* tp_as_buffer      */ 0,
+    /* tp_flags          */ Py_TPFLAGS_DEFAULT,
+    /* tp_doc            */ "PDF Outline items",
+    /* tp_traverse       */ 0,
+    /* tp_clear          */ 0,
+    /* tp_richcompare    */ 0,
+    /* tp_weaklistoffset */ 0,
+    /* tp_iter           */ 0,
+    /* tp_iternext       */ 0,
+    /* tp_methods        */ methods,
+    /* tp_members        */ 0,
+    /* tp_getset         */ 0,
+    /* tp_base           */ 0,
+    /* tp_dict           */ 0,
+    /* tp_descr_get      */ 0,
+    /* tp_descr_set      */ 0,
+    /* tp_dictoffset     */ 0,
+    /* tp_init           */ 0,
+    /* tp_alloc          */ 0,
+    /* tp_new            */ new_item,
 };
 // }}}
diff --git a/src/calibre/utils/podofo/output.cpp b/src/calibre/utils/podofo/output.cpp
index a03cc0b188..106b4ae763 100644
--- a/src/calibre/utils/podofo/output.cpp
+++ b/src/calibre/utils/podofo/output.cpp
@@ -97,7 +97,11 @@ class OutputDevice : public PdfOutputDevice {
             char *buf = NULL;
             Py_ssize_t len = 0;
 
+#if PY_MAJOR_VERSION >= 3
+            if ((temp = PyLong_FromSize_t(lLen)) == NULL) throw pyerr();
+#else
             if ((temp = PyInt_FromSize_t(lLen)) == NULL) throw pyerr();
+#endif
             ret = PyObject_CallFunctionObjArgs(read_func, temp, NULL);
             NUKE(temp);
             if (ret != NULL) {
@@ -118,7 +122,11 @@ class OutputDevice : public PdfOutputDevice {
 
         void Seek(size_t offset) {
             PyObject *ret, *temp;
+#if PY_MAJOR_VERSION >= 3
+            if ((temp = PyLong_FromSize_t(offset)) == NULL) throw pyerr();
+#else
             if ((temp = PyInt_FromSize_t(offset)) == NULL) throw pyerr();
+#endif
             ret = PyObject_CallFunctionObjArgs(seek_func, temp, NULL);
             NUKE(temp);
             if (ret == NULL) {
@@ -144,7 +152,11 @@ class OutputDevice : public PdfOutputDevice {
                 PyErr_SetString(PyExc_Exception, "tell() method did not return a number");
                 throw pyerr();
             }
+#if PY_MAJOR_VERSION >= 3
+            ans = PyLong_AsUnsignedLongMask(ret);
+#else
             ans = PyInt_AsUnsignedLongMask(ret);
+#endif
             Py_DECREF(ret);
             if (PyErr_Occurred() != NULL) throw pyerr();
 
@@ -191,4 +203,3 @@ PyObject* pdf::write_doc(PdfMemDocument *doc, PyObject *f) {
 
     Py_RETURN_NONE;
 }
-
diff --git a/src/calibre/utils/podofo/podofo.cpp b/src/calibre/utils/podofo/podofo.cpp
index 50f20de8cf..517f4cbf80 100644
--- a/src/calibre/utils/podofo/podofo.cpp
+++ b/src/calibre/utils/podofo/podofo.cpp
@@ -10,10 +10,6 @@ using namespace PoDoFo;
 
 PyObject *pdf::Error = NULL;
 
-static PyMethodDef podofo_methods[] = {
-    {NULL}  /* Sentinel */
-};
-
 class PyLogMessage : public PdfError::LogMessageCallback {
 
     public:
@@ -38,29 +34,63 @@ class PyLogMessage : public PdfError::LogMessageCallback {
 
 PyLogMessage log_message;
 
-CALIBRE_MODINIT_FUNC
-initpodofo(void)
-{
+static char podofo_doc[] = "Wrapper for the PoDoFo PDF library";
+
+static PyMethodDef podofo_methods[] = {
+    {NULL}  /* Sentinel */
+};
+
+#if PY_MAJOR_VERSION >= 3
+#define INITERROR return NULL
+#define INITMODULE PyModule_Create(&podofo_module)
+static struct PyModuleDef podofo_module = {
+    /* m_base     */ PyModuleDef_HEAD_INIT,
+    /* m_name     */ "podofo",
+    /* m_doc      */ podofo_doc,
+    /* m_size     */ -1,
+    /* m_methods  */ podofo_methods,
+    /* m_slots    */ 0,
+    /* m_traverse */ 0,
+    /* m_clear    */ 0,
+    /* m_free     */ 0,
+};
+CALIBRE_MODINIT_FUNC PyInit_podofo(void) {
+#else
+#define INITERROR return
+#define INITMODULE Py_InitModule3("podofo", podofo_methods, podofo_doc)
+CALIBRE_MODINIT_FUNC initpodofo(void) {
+#endif
+
     PyObject* m;
 
-    if (PyType_Ready(&pdf::PDFDocType) < 0)
-        return;
+    if (PyType_Ready(&pdf::PDFDocType) < 0) {
+        INITERROR;
+    }
 
-    if (PyType_Ready(&pdf::PDFOutlineItemType) < 0)
-        return;
+    if (PyType_Ready(&pdf::PDFOutlineItemType) < 0) {
+        INITERROR;
+    }
 
     pdf::Error = PyErr_NewException((char*)"podofo.Error", NULL, NULL);
-    if (pdf::Error == NULL) return;
+    if (pdf::Error == NULL) {
+        INITERROR;
+    }
 
     PdfError::SetLogMessageCallback((PdfError::LogMessageCallback*)&log_message);
 
     PdfError::EnableDebug(false);
-    m = Py_InitModule3("podofo", podofo_methods,
-                       "Wrapper for the PoDoFo PDF library");
+
+    m = INITMODULE;
+    if (m == NULL) {
+        INITERROR;
+    }
 
     Py_INCREF(&pdf::PDFDocType);
     PyModule_AddObject(m, "PDFDoc", (PyObject *)&pdf::PDFDocType);
 
     PyModule_AddObject(m, "Error", pdf::Error);
-}
 
+#if PY_MAJOR_VERSION >= 3
+    return m;
+#endif
+}
diff --git a/src/lzma/lzma_binding.c b/src/lzma/lzma_binding.c
index 24dd28e60a..d02f14c523 100644
--- a/src/lzma/lzma_binding.c
+++ b/src/lzma/lzma_binding.c
@@ -58,6 +58,12 @@ static PyObject *LZMAError = NULL;
 // Utils {{{
 static UInt64 crc64_table[256];
 
+#if PY_MAJOR_VERSION >= 3
+    #define BYTES_FMT "y#"
+#else
+    #define BYTES_FMT "s#"
+#endif
+
 static void init_crc_table() {
     static const UInt64 poly64 = (UInt64)(0xC96C5795D7870F42);
     size_t i, j;
@@ -79,7 +85,7 @@ crc64(PyObject *self, PyObject *args) {
     Py_ssize_t size = 0;
     UInt64 crc = 0;
     size_t i;
-    if (!PyArg_ParseTuple(args, "s#|K", &data, &size, &crc)) return NULL;
+    if (!PyArg_ParseTuple(args, BYTES_FMT "|K", &data, &size, &crc)) return NULL;
     crc = ~crc;
     for (i = 0; i < (size_t)size; ++i)
         crc = crc64_table[data[i] ^ (crc & 0xFF)] ^ (crc >> 8);
@@ -142,7 +148,7 @@ decompress2(PyObject *self, PyObject *args) {
         } else { res = SZ_OK; bytes_written = 0; status = LZMA_STATUS_NEEDS_MORE_INPUT; }
         if (res != SZ_OK) { SET_ERROR(res); goto exit; }
         if (bytes_written > 0) {
-            if(!PyObject_CallFunction(write, "s#", outbuf, bytes_written)) goto exit;
+            if(!PyObject_CallFunction(write, BYTES_FMT, outbuf, bytes_written)) goto exit;
         }
         if (inbuf_len > inbuf_pos && !bytes_read && !bytes_written && status != LZMA_STATUS_NEEDS_MORE_INPUT && status != LZMA_STATUS_FINISHED_WITH_MARK) {
             SET_ERROR(SZ_ERROR_DATA); goto exit;
@@ -188,7 +194,7 @@ decompress(PyObject *self, PyObject *args) {
     ELzmaStatus status = LZMA_STATUS_NOT_FINISHED;
     ELzmaFinishMode finish_mode = LZMA_FINISH_ANY;
 
-    if(!PyArg_ParseTuple(args, "OOOKs#k", &read, &seek, &write, &decompressed_size, &header, &header_size, &bufsize)) return NULL;
+    if(!PyArg_ParseTuple(args, "OOOK" BYTES_FMT "k", &read, &seek, &write, &decompressed_size, &header, &header_size, &bufsize)) return NULL;
     size_known = (decompressed_size != (UInt64)(Int64)-1);
     if (header_size != 13) { PyErr_SetString(LZMAError, "Header must be exactly 13 bytes long"); return NULL; }
     if (!decompressed_size) { PyErr_SetString(LZMAError, "Cannot decompress empty file"); return NULL; }
@@ -214,7 +220,7 @@ decompress(PyObject *self, PyObject *args) {
         } else { res = SZ_OK; bytes_written = 0; status = LZMA_STATUS_NEEDS_MORE_INPUT; }
         if (res != SZ_OK) { SET_ERROR(res); goto exit; }
         if (bytes_written > 0) {
-            if(!PyObject_CallFunction(write, "s#", outbuf, bytes_written)) goto exit;
+            if(!PyObject_CallFunction(write, BYTES_FMT, outbuf, bytes_written)) goto exit;
             total_written += bytes_written;
         }
         if (inbuf_len > inbuf_pos && !bytes_read && !bytes_written && status != LZMA_STATUS_NEEDS_MORE_INPUT && status != LZMA_STATUS_FINISHED_WITH_MARK) {
@@ -296,7 +302,7 @@ static size_t owrite(void *p, const void *buf, size_t size) {
     PyObject *res = NULL;
     if (!size) return 0;
     ACQUIRE_GIL
-    res = PyObject_CallFunction(self->write, "s#", (char*)buf, size);
+    res = PyObject_CallFunction(self->write, BYTES_FMT, (char*)buf, size);
     if (res == NULL) return 0;
     Py_DECREF(res);
     RELEASE_GIL
@@ -332,7 +338,7 @@ get_lzma2_properties(int preset) {
 exit:
     if (lzma2) Lzma2Enc_Destroy(lzma2);
     if (PyErr_Occurred()) return NULL;
-    return Py_BuildValue("s#", &props_out, 1);
+    return Py_BuildValue(BYTES_FMT, &props_out, 1);
 }
 
 
@@ -382,7 +388,7 @@ compress(PyObject *self, PyObject *args) {
 exit:
     if (lzma2) Lzma2Enc_Destroy(lzma2);
     if (PyErr_Occurred()) return NULL;
-    return Py_BuildValue("s#", &props_out, 1);
+    return Py_BuildValue(BYTES_FMT, &props_out, 1);
 }
 
 // }}}