diff --git a/ebook_converter/__init__.py b/ebook_converter/__init__.py
index 0c04224..9564a1b 100644
--- a/ebook_converter/__init__.py
+++ b/ebook_converter/__init__.py
@@ -15,7 +15,7 @@ try:
 except EnvironmentError:
     os.chdir(os.path.expanduser('~'))
 
-from ebook_converter.constants import (iswindows, isosx, islinux, isfrozen,
+from ebook_converter.constants_old import (iswindows, isosx, islinux, isfrozen,
         isbsd, preferred_encoding, __appname__, __version__, __author__,
         win32event, win32api, winerror, fcntl,
         filesystem_encoding, plugins, config_dir)
diff --git a/ebook_converter/constants.py b/ebook_converter/constants_old.py
similarity index 100%
rename from ebook_converter/constants.py
rename to ebook_converter/constants_old.py
diff --git a/ebook_converter/customize/__init__.py b/ebook_converter/customize/__init__.py
index 3c9d9c2..8967a0f 100644
--- a/ebook_converter/customize/__init__.py
+++ b/ebook_converter/customize/__init__.py
@@ -2,7 +2,7 @@ import importlib
 import sys
 import zipfile
 
-from ebook_converter.constants import numeric_version, iswindows, isosx
+from ebook_converter.constants_old import numeric_version, iswindows, isosx
 from ebook_converter.ptempfile import PersistentTemporaryFile
 
 
diff --git a/ebook_converter/customize/builtins.py b/ebook_converter/customize/builtins.py
index 55c980a..df820c9 100644
--- a/ebook_converter/customize/builtins.py
+++ b/ebook_converter/customize/builtins.py
@@ -3,7 +3,7 @@ import os, glob, re
 from ebook_converter import guess_type
 from ebook_converter.customize import (FileTypePlugin, MetadataReaderPlugin,
     MetadataWriterPlugin, PreferencesPlugin, InterfaceActionBase, StoreBase)
-from ebook_converter.constants import numeric_version
+from ebook_converter.constants_old import numeric_version
 from ebook_converter.ebooks.metadata.archive import ArchiveExtract, KPFExtract, get_comic_metadata
 from ebook_converter.ebooks.html.to_zip import HTML2ZIP
 
diff --git a/ebook_converter/devices/interface.py b/ebook_converter/devices/interface.py
index 40c46bc..0c0727c 100644
--- a/ebook_converter/devices/interface.py
+++ b/ebook_converter/devices/interface.py
@@ -2,7 +2,7 @@ import os
 from collections import namedtuple
 
 from ebook_converter import prints
-from ebook_converter.constants import iswindows
+from ebook_converter.constants_old import iswindows
 from ebook_converter.customize import Plugin
 
 
diff --git a/ebook_converter/ebooks/chardet.py b/ebook_converter/ebooks/chardet.py
index 5428e45..ca686b7 100644
--- a/ebook_converter/ebooks/chardet.py
+++ b/ebook_converter/ebooks/chardet.py
@@ -108,7 +108,7 @@ def detect(*args, **kwargs):
 
 
 def force_encoding(raw, verbose, assume_utf8=False):
-    from ebook_converter.constants import preferred_encoding
+    from ebook_converter.constants_old import preferred_encoding
 
     try:
         chardet = detect(raw[:1024*50])
diff --git a/ebook_converter/ebooks/conversion/cli.py b/ebook_converter/ebooks/conversion/cli.py
index b71c9e9..7bb39d0 100644
--- a/ebook_converter/ebooks/conversion/cli.py
+++ b/ebook_converter/ebooks/conversion/cli.py
@@ -282,7 +282,7 @@ class ProgressBar(object):
 
 def create_option_parser(args, log):
     if '--version' in args:
-        from ebook_converter.constants import __appname__, __version__, __author__
+        from ebook_converter.constants_old import __appname__, __version__, __author__
         log(os.path.basename(args[0]), '('+__appname__, __version__+')')
         log('Created by:', __author__)
         raise SystemExit(0)
diff --git a/ebook_converter/ebooks/conversion/plugins/chm_input.py b/ebook_converter/ebooks/conversion/plugins/chm_input.py
index a4bb43d..2ee6e92 100644
--- a/ebook_converter/ebooks/conversion/plugins/chm_input.py
+++ b/ebook_converter/ebooks/conversion/plugins/chm_input.py
@@ -10,7 +10,7 @@ from ebook_converter.ebooks.oeb.base import urlquote
 from ebook_converter.ebooks.chardet import xml_to_unicode
 from ebook_converter.customize.conversion import InputFormatPlugin
 from ebook_converter.ptempfile import TemporaryDirectory
-from ebook_converter.constants import filesystem_encoding
+from ebook_converter.constants_old import filesystem_encoding
 from ebook_converter.polyglot.builtins import as_bytes
 
 __license__ = 'GPL v3'
diff --git a/ebook_converter/ebooks/conversion/plugins/html_input.py b/ebook_converter/ebooks/conversion/plugins/html_input.py
index 484c9c9..7428231 100644
--- a/ebook_converter/ebooks/conversion/plugins/html_input.py
+++ b/ebook_converter/ebooks/conversion/plugins/html_input.py
@@ -4,7 +4,7 @@ import re
 import tempfile
 import urllib.parse
 
-from ebook_converter.constants import islinux, isbsd
+from ebook_converter.constants_old import islinux, isbsd
 from ebook_converter.customize.conversion import (InputFormatPlugin,
         OptionRecommendation)
 from ebook_converter.utils.localization import get_lang
diff --git a/ebook_converter/ebooks/conversion/plugins/lrf_output.py b/ebook_converter/ebooks/conversion/plugins/lrf_output.py
index 727ac10..5653095 100644
--- a/ebook_converter/ebooks/conversion/plugins/lrf_output.py
+++ b/ebook_converter/ebooks/conversion/plugins/lrf_output.py
@@ -139,7 +139,7 @@ class LRFOutput(OutputFormatPlugin):
     def convert_images(self, pages, opts, wide):
         from ebook_converter.ebooks.lrf.pylrs.pylrs import Book, BookSetting, ImageStream, ImageBlock
         from uuid import uuid4
-        from ebook_converter.constants import __appname__, __version__
+        from ebook_converter.constants_old import __appname__, __version__
 
         width, height = (784, 1012) if wide else (584, 754)
 
diff --git a/ebook_converter/ebooks/conversion/plugins/pdf_output.py b/ebook_converter/ebooks/conversion/plugins/pdf_output.py
index c2325e5..50d6d39 100644
--- a/ebook_converter/ebooks/conversion/plugins/pdf_output.py
+++ b/ebook_converter/ebooks/conversion/plugins/pdf_output.py
@@ -144,7 +144,7 @@ class PDFOutput(OutputFormatPlugin):
         from PyQt5.QtWebEngineCore import QWebEngineUrlScheme
         from PyQt5.QtWebEngineWidgets import QWebEnginePage  # noqa
         from ebook_converter.gui2 import must_use_qt
-        from ebook_converter.constants import FAKE_PROTOCOL
+        from ebook_converter.constants_old import FAKE_PROTOCOL
         scheme = QWebEngineUrlScheme(FAKE_PROTOCOL.encode('ascii'))
         scheme.setSyntax(QWebEngineUrlScheme.Syntax.Host)
         scheme.setFlags(QWebEngineUrlScheme.SecureScheme)
diff --git a/ebook_converter/ebooks/conversion/plugins/recipe_input.py b/ebook_converter/ebooks/conversion/plugins/recipe_input.py
index 519477f..6cf5f0d 100644
--- a/ebook_converter/ebooks/conversion/plugins/recipe_input.py
+++ b/ebook_converter/ebooks/conversion/plugins/recipe_input.py
@@ -1,7 +1,7 @@
 import os
 
 from ebook_converter.customize.conversion import InputFormatPlugin, OptionRecommendation
-from ebook_converter.constants import numeric_version
+from ebook_converter.constants_old import numeric_version
 from ebook_converter import walk
 
 
diff --git a/ebook_converter/ebooks/conversion/plugins/snb_output.py b/ebook_converter/ebooks/conversion/plugins/snb_output.py
index 0a4a1ff..af3dcff 100644
--- a/ebook_converter/ebooks/conversion/plugins/snb_output.py
+++ b/ebook_converter/ebooks/conversion/plugins/snb_output.py
@@ -2,7 +2,7 @@ import os
 
 from ebook_converter.customize.conversion import OutputFormatPlugin, OptionRecommendation
 from ebook_converter.ptempfile import TemporaryDirectory
-from ebook_converter.constants import __appname__, __version__
+from ebook_converter.constants_old import __appname__, __version__
 
 
 __license__ = 'GPL 3'
diff --git a/ebook_converter/ebooks/conversion/plumber.py b/ebook_converter/ebooks/conversion/plumber.py
index 3eadb8b..2d9323c 100644
--- a/ebook_converter/ebooks/conversion/plumber.py
+++ b/ebook_converter/ebooks/conversion/plumber.py
@@ -16,7 +16,7 @@ from ebook_converter.utils.date import parse_date
 from ebook_converter.utils.zipfile import ZipFile
 from ebook_converter import (extract, walk, isbytestring, filesystem_encoding,
                              get_types_map)
-from ebook_converter.constants import __version__
+from ebook_converter.constants_old import __version__
 
 
 DEBUG_README=b'''
diff --git a/ebook_converter/ebooks/covers.py b/ebook_converter/ebooks/covers.py
index bdafe2a..e5011d8 100644
--- a/ebook_converter/ebooks/covers.py
+++ b/ebook_converter/ebooks/covers.py
@@ -11,7 +11,7 @@ from PyQt5.Qt import (
 )
 
 from ebook_converter import force_unicode, fit_image
-from ebook_converter.constants import __appname__, __version__
+from ebook_converter.constants_old import __appname__, __version__
 from ebook_converter.ebooks.metadata import fmt_sidx
 from ebook_converter.ebooks.metadata.book.base import Metadata
 from ebook_converter.ebooks.metadata.book.formatter import SafeFormat
diff --git a/ebook_converter/ebooks/docx/images.py b/ebook_converter/ebooks/docx/images.py
index 4432062..ead223a 100644
--- a/ebook_converter/ebooks/docx/images.py
+++ b/ebook_converter/ebooks/docx/images.py
@@ -2,7 +2,7 @@ import os
 
 from lxml.html.builder import IMG, HR
 
-from ebook_converter.constants import iswindows
+from ebook_converter.constants_old import iswindows
 from ebook_converter.ebooks.docx.names import barename
 from ebook_converter.utils.filenames import ascii_filename
 from ebook_converter.utils.img import resize_to_fit, image_to_data
diff --git a/ebook_converter/ebooks/docx/writer/container.py b/ebook_converter/ebooks/docx/writer/container.py
index 46d6e0c..015af68 100644
--- a/ebook_converter/ebooks/docx/writer/container.py
+++ b/ebook_converter/ebooks/docx/writer/container.py
@@ -4,7 +4,7 @@ from lxml import etree
 from lxml.builder import ElementMaker
 
 from ebook_converter import guess_type
-from ebook_converter.constants import numeric_version, __appname__
+from ebook_converter.constants_old import numeric_version, __appname__
 from ebook_converter.ebooks.docx.names import DOCXNamespace
 from ebook_converter.ebooks.metadata import authors_to_string
 from ebook_converter.ebooks.pdf.render.common import PAPER_SIZES
diff --git a/ebook_converter/ebooks/fb2/fb2ml.py b/ebook_converter/ebooks/fb2/fb2ml.py
index f8b718c..9db7965 100644
--- a/ebook_converter/ebooks/fb2/fb2ml.py
+++ b/ebook_converter/ebooks/fb2/fb2ml.py
@@ -10,7 +10,7 @@ import uuid
 from lxml import etree
 
 from ebook_converter import prepare_string_for_xml
-from ebook_converter.constants import __appname__, __version__
+from ebook_converter.constants_old import __appname__, __version__
 from ebook_converter.utils.localization import lang_as_iso639_1
 from ebook_converter.utils.xml_parse import safe_xml_fromstring
 from ebook_converter.utils.img import save_cover_data_to
diff --git a/ebook_converter/ebooks/html/input.py b/ebook_converter/ebooks/html/input.py
index 6c35af0..3a61e1d 100644
--- a/ebook_converter/ebooks/html/input.py
+++ b/ebook_converter/ebooks/html/input.py
@@ -9,7 +9,7 @@ import urllib.parse
 
 from ebook_converter.ebooks.oeb.base import urlunquote
 from ebook_converter.ebooks.chardet import detect_xml_encoding
-from ebook_converter.constants import iswindows
+from ebook_converter.constants_old import iswindows
 from ebook_converter import unicode_path, as_unicode, replace_entities
 
 
diff --git a/ebook_converter/ebooks/html/to_zip.py b/ebook_converter/ebooks/html/to_zip.py
index f6f4034..9cdb276 100644
--- a/ebook_converter/ebooks/html/to_zip.py
+++ b/ebook_converter/ebooks/html/to_zip.py
@@ -1,7 +1,7 @@
 import textwrap, os, glob
 
 from ebook_converter.customize import FileTypePlugin
-from ebook_converter.constants import numeric_version
+from ebook_converter.constants_old import numeric_version
 
 
 __license__ = 'GPL v3'
diff --git a/ebook_converter/ebooks/lrf/html/convert_from.py b/ebook_converter/ebooks/lrf/html/convert_from.py
index 0b38059..7b35760 100644
--- a/ebook_converter/ebooks/lrf/html/convert_from.py
+++ b/ebook_converter/ebooks/lrf/html/convert_from.py
@@ -23,7 +23,7 @@ import bs4
 from ebook_converter import (
     __appname__, entity_to_unicode, fit_image, force_unicode, preferred_encoding
 )
-from ebook_converter.constants import filesystem_encoding
+from ebook_converter.constants_old import filesystem_encoding
 from ebook_converter.devices.interface import DevicePlugin as Device
 from ebook_converter.ebooks import ConversionError
 from ebook_converter.ebooks.BeautifulSoup import html5_parser
diff --git a/ebook_converter/ebooks/lrf/meta.py b/ebook_converter/ebooks/lrf/meta.py
index 248e3b7..27501d4 100644
--- a/ebook_converter/ebooks/lrf/meta.py
+++ b/ebook_converter/ebooks/lrf/meta.py
@@ -622,7 +622,7 @@ class LRFMetaFile(object):
 
 def option_parser():
     from ebook_converter.utils.config import OptionParser
-    from ebook_converter.constants import __appname__, __version__
+    from ebook_converter.constants_old import __appname__, __version__
     parser = OptionParser(usage=('''%prog [options] mybook.lrf
 
 
diff --git a/ebook_converter/ebooks/metadata/book/base.py b/ebook_converter/ebooks/metadata/book/base.py
index 116c05d..ecce2b9 100644
--- a/ebook_converter/ebooks/metadata/book/base.py
+++ b/ebook_converter/ebooks/metadata/book/base.py
@@ -1,7 +1,7 @@
 import copy, traceback
 
 from ebook_converter import prints
-from ebook_converter.constants import DEBUG
+from ebook_converter.constants_old import DEBUG
 from ebook_converter.ebooks.metadata.book import (SC_COPYABLE_FIELDS,
         SC_FIELDS_COPY_NOT_NULL, STANDARD_METADATA_FIELDS,
         TOP_LEVEL_IDENTIFIERS, ALL_METADATA_FIELDS)
diff --git a/ebook_converter/ebooks/metadata/book/json_codec.py b/ebook_converter/ebooks/metadata/book/json_codec.py
index c9d243c..6dcdb62 100644
--- a/ebook_converter/ebooks/metadata/book/json_codec.py
+++ b/ebook_converter/ebooks/metadata/book/json_codec.py
@@ -7,7 +7,7 @@ import json, traceback
 from datetime import datetime, time
 
 from ebook_converter.ebooks.metadata.book import SERIALIZABLE_FIELDS
-from ebook_converter.constants import filesystem_encoding, preferred_encoding
+from ebook_converter.constants_old import filesystem_encoding, preferred_encoding
 from ebook_converter.library.field_metadata import FieldMetadata
 from ebook_converter import isbytestring
 from ebook_converter.polyglot.builtins import as_bytes
diff --git a/ebook_converter/ebooks/metadata/meta.py b/ebook_converter/ebooks/metadata/meta.py
index b26d7b9..131e14e 100644
--- a/ebook_converter/ebooks/metadata/meta.py
+++ b/ebook_converter/ebooks/metadata/meta.py
@@ -1,7 +1,7 @@
 import os, re, collections
 
 from ebook_converter.utils.config import prefs
-from ebook_converter.constants import filesystem_encoding
+from ebook_converter.constants_old import filesystem_encoding
 from ebook_converter.ebooks.metadata.opf2 import OPF
 from ebook_converter import isbytestring
 from ebook_converter.customize.ui import get_file_type_metadata, set_file_type_metadata
diff --git a/ebook_converter/ebooks/metadata/opf2.py b/ebook_converter/ebooks/metadata/opf2.py
index 4e0fb51..586164b 100644
--- a/ebook_converter/ebooks/metadata/opf2.py
+++ b/ebook_converter/ebooks/metadata/opf2.py
@@ -16,7 +16,8 @@ import uuid
 from lxml import etree
 
 from ebook_converter.ebooks import escape_xpath_attr
-from ebook_converter.constants import __appname__, __version__, filesystem_encoding
+from ebook_converter.constants_old import __appname__, __version__, \
+        filesystem_encoding
 from ebook_converter.ebooks.metadata.toc import TOC
 from ebook_converter.ebooks.metadata.utils import parse_opf, pretty_print_opf as _pretty_print
 from ebook_converter.ebooks.metadata import string_to_authors, MetaInformation, check_isbn
diff --git a/ebook_converter/ebooks/metadata/pdf.py b/ebook_converter/ebooks/metadata/pdf.py
index a6c1ae9..f8a09d1 100644
--- a/ebook_converter/ebooks/metadata/pdf.py
+++ b/ebook_converter/ebooks/metadata/pdf.py
@@ -5,7 +5,7 @@ import os, subprocess, shutil, re
 from functools import partial
 
 from ebook_converter import prints
-from ebook_converter.constants import iswindows
+from ebook_converter.constants_old import iswindows
 from ebook_converter.ptempfile import TemporaryDirectory
 from ebook_converter.ebooks.metadata import (
     MetaInformation, string_to_authors, check_isbn, check_doi)
diff --git a/ebook_converter/ebooks/metadata/toc.py b/ebook_converter/ebooks/metadata/toc.py
index 72a3c04..a9330a4 100644
--- a/ebook_converter/ebooks/metadata/toc.py
+++ b/ebook_converter/ebooks/metadata/toc.py
@@ -8,7 +8,7 @@ import urllib.parse
 from lxml import etree
 from lxml.builder import ElementMaker
 
-from ebook_converter.constants import __appname__, __version__
+from ebook_converter.constants_old import __appname__, __version__
 from ebook_converter.ebooks.chardet import xml_to_unicode
 from ebook_converter.utils.xml_parse import safe_xml_fromstring
 from ebook_converter.utils.cleantext import clean_xml_chars
diff --git a/ebook_converter/ebooks/mobi/writer8/exth.py b/ebook_converter/ebooks/mobi/writer8/exth.py
index ef91fa1..435aa23 100644
--- a/ebook_converter/ebooks/mobi/writer8/exth.py
+++ b/ebook_converter/ebooks/mobi/writer8/exth.py
@@ -2,7 +2,7 @@ import re
 from struct import pack
 from io import BytesIO
 
-from ebook_converter.constants import iswindows, isosx
+from ebook_converter.constants_old import iswindows, isosx
 from ebook_converter.ebooks.mobi.utils import (utf8_text, to_base)
 from ebook_converter.utils.localization import lang_as_iso639_1
 from ebook_converter.ebooks.metadata import authors_to_sort_string
diff --git a/ebook_converter/ebooks/oeb/base.py b/ebook_converter/ebooks/oeb/base.py
index f7a5193..2862fd9 100644
--- a/ebook_converter/ebooks/oeb/base.py
+++ b/ebook_converter/ebooks/oeb/base.py
@@ -10,7 +10,7 @@ import string
 
 from lxml import etree, html
 from ebook_converter import force_unicode
-from ebook_converter.constants import filesystem_encoding, __version__
+from ebook_converter.constants_old import filesystem_encoding, __version__
 from ebook_converter.utils.xml_parse import safe_xml_fromstring
 from ebook_converter.ebooks.chardet import xml_to_unicode
 from ebook_converter.ebooks.conversion.preprocess import CSSPreProcessor
diff --git a/ebook_converter/ebooks/oeb/parse_utils.py b/ebook_converter/ebooks/oeb/parse_utils.py
index 39c60ea..64be9f2 100644
--- a/ebook_converter/ebooks/oeb/parse_utils.py
+++ b/ebook_converter/ebooks/oeb/parse_utils.py
@@ -4,7 +4,7 @@ from lxml import etree, html
 
 from ebook_converter import xml_replace_entities, force_unicode
 from ebook_converter.utils.xml_parse import safe_xml_fromstring
-from ebook_converter.constants import filesystem_encoding
+from ebook_converter.constants_old import filesystem_encoding
 from ebook_converter.ebooks.chardet import xml_to_unicode, strip_encoding_declarations
 
 
diff --git a/ebook_converter/ebooks/oeb/polish/container.py b/ebook_converter/ebooks/oeb/polish/container.py
index c479649..e3b9530 100644
--- a/ebook_converter/ebooks/oeb/polish/container.py
+++ b/ebook_converter/ebooks/oeb/polish/container.py
@@ -16,7 +16,7 @@ import urllib.parse
 from css_parser import getUrls, replaceUrls
 
 from ebook_converter import CurrentDir, walk
-from ebook_converter.constants import iswindows
+from ebook_converter.constants_old import iswindows
 from ebook_converter.customize.ui import plugin_for_input_format, plugin_for_output_format
 from ebook_converter.ebooks import escape_xpath_attr
 from ebook_converter.ebooks.chardet import xml_to_unicode
diff --git a/ebook_converter/ebooks/oeb/reader.py b/ebook_converter/ebooks/oeb/reader.py
index 1cf22c8..4139b1b 100644
--- a/ebook_converter/ebooks/oeb/reader.py
+++ b/ebook_converter/ebooks/oeb/reader.py
@@ -21,7 +21,7 @@ from ebook_converter.utils.xml_parse import safe_xml_fromstring
 from ebook_converter.utils.cleantext import clean_xml_chars
 from ebook_converter.utils.localization import get_lang
 from ebook_converter.ptempfile import TemporaryDirectory
-from ebook_converter.constants import __appname__, __version__
+from ebook_converter.constants_old import __appname__, __version__
 from ebook_converter import guess_type, xml_replace_entities
 from ebook_converter.polyglot.urllib import unquote
 
diff --git a/ebook_converter/ebooks/oeb/transforms/jacket.py b/ebook_converter/ebooks/oeb/transforms/jacket.py
index cb1ee01..0d1a88b 100644
--- a/ebook_converter/ebooks/oeb/transforms/jacket.py
+++ b/ebook_converter/ebooks/oeb/transforms/jacket.py
@@ -5,7 +5,7 @@ import pkg_resources
 import urllib.parse
 
 from ebook_converter import guess_type, strftime
-from ebook_converter.constants import iswindows
+from ebook_converter.constants_old import iswindows
 from ebook_converter.ebooks.oeb.base import XPath, XHTML_NS, XHTML, xml2text, urlnormalize
 from ebook_converter.library.comments import comments_to_html, markdown
 from ebook_converter.utils.date import is_date_undefined, as_local_time
diff --git a/ebook_converter/ebooks/pdf/pdftohtml.py b/ebook_converter/ebooks/pdf/pdftohtml.py
index 2a317f9..d10cd82 100644
--- a/ebook_converter/ebooks/pdf/pdftohtml.py
+++ b/ebook_converter/ebooks/pdf/pdftohtml.py
@@ -6,7 +6,7 @@ import subprocess
 import sys
 
 from ebook_converter import CurrentDir, xml_replace_entities, prints
-from ebook_converter.constants import (
+from ebook_converter.constants_old import (
     filesystem_encoding, isbsd, islinux, isosx, iswindows
 )
 from ebook_converter.ebooks import ConversionError, DRMError
diff --git a/ebook_converter/library/__init__.py b/ebook_converter/library/__init__.py
index 729a4b8..ff4c1d5 100644
--- a/ebook_converter/library/__init__.py
+++ b/ebook_converter/library/__init__.py
@@ -26,7 +26,7 @@ def generate_test_db(library_path,  # {{{
         max_tags=10
         ):
     import random, string, os, sys, time
-    from ebook_converter.constants import preferred_encoding
+    from ebook_converter.constants_old import preferred_encoding
 
     if not os.path.exists(library_path):
         os.makedirs(library_path)
diff --git a/ebook_converter/library/comments.py b/ebook_converter/library/comments.py
index 8aefe84..05a8a64 100644
--- a/ebook_converter/library/comments.py
+++ b/ebook_converter/library/comments.py
@@ -3,7 +3,7 @@ import re
 import bs4
 
 from ebook_converter import prepare_string_for_xml
-from ebook_converter.constants import preferred_encoding
+from ebook_converter.constants_old import preferred_encoding
 from ebook_converter.ebooks.BeautifulSoup import html5_parser
 from ebook_converter.utils.html2text import html2text
 
diff --git a/ebook_converter/ptempfile.py b/ebook_converter/ptempfile.py
index 5dca4f7..97d645e 100644
--- a/ebook_converter/ptempfile.py
+++ b/ebook_converter/ptempfile.py
@@ -6,7 +6,7 @@ being closed.
 """
 import tempfile, os, atexit
 
-from ebook_converter.constants import (__version__, __appname__, filesystem_encoding,
+from ebook_converter.constants_old import (__version__, __appname__, filesystem_encoding,
         iswindows, get_windows_temp_path, isosx)
 
 
diff --git a/ebook_converter/utils/cleantext.py b/ebook_converter/utils/cleantext.py
index c2079b7..37f045d 100644
--- a/ebook_converter/utils/cleantext.py
+++ b/ebook_converter/utils/cleantext.py
@@ -1,7 +1,7 @@
 import re
 import html.entities
 
-from ebook_converter.constants import plugins, preferred_encoding
+from ebook_converter.constants_old import plugins, preferred_encoding
 
 
 def ascii_pat(for_binary=False):
diff --git a/ebook_converter/utils/config.py b/ebook_converter/utils/config.py
index bc89d19..02b1860 100644
--- a/ebook_converter/utils/config.py
+++ b/ebook_converter/utils/config.py
@@ -5,7 +5,7 @@ import optparse
 import os
 from copy import deepcopy
 
-from ebook_converter.constants import (
+from ebook_converter.constants_old import (
     CONFIG_DIR_MODE, __appname__, __author__, config_dir, get_version, iswindows
 )
 from ebook_converter.utils.config_base import (
diff --git a/ebook_converter/utils/config_base.py b/ebook_converter/utils/config_base.py
index d17ae70..e452974 100644
--- a/ebook_converter/utils/config_base.py
+++ b/ebook_converter/utils/config_base.py
@@ -9,7 +9,7 @@ from copy import deepcopy
 import pkg_resources
 
 from ebook_converter.utils.lock import ExclusiveFile
-from ebook_converter.constants import config_dir, CONFIG_DIR_MODE, preferred_encoding, filesystem_encoding, iswindows
+from ebook_converter.constants_old import config_dir, CONFIG_DIR_MODE, preferred_encoding, filesystem_encoding, iswindows
 
 plugin_dir = os.path.join(config_dir, 'plugins')
 
diff --git a/ebook_converter/utils/date.py b/ebook_converter/utils/date.py
index 34ee7c0..db53b0d 100644
--- a/ebook_converter/utils/date.py
+++ b/ebook_converter/utils/date.py
@@ -3,7 +3,7 @@ from datetime import datetime, time as dtime, timedelta, MINYEAR, MAXYEAR
 from functools import partial
 
 from ebook_converter import strftime
-from ebook_converter.constants import iswindows, isosx, plugins, preferred_encoding
+from ebook_converter.constants_old import iswindows, isosx, plugins, preferred_encoding
 from ebook_converter.utils.iso8601 import utc_tz, local_tz, UNDEFINED_DATE
 from ebook_converter.utils.localization import lcdata
 
diff --git a/ebook_converter/utils/filenames.py b/ebook_converter/utils/filenames.py
index 8172e77..c37d439 100644
--- a/ebook_converter/utils/filenames.py
+++ b/ebook_converter/utils/filenames.py
@@ -9,7 +9,7 @@ import time
 from math import ceil
 
 from ebook_converter import force_unicode, isbytestring, prints, sanitize_file_name
-from ebook_converter.constants import (
+from ebook_converter.constants_old import (
     filesystem_encoding, iswindows, plugins, preferred_encoding, isosx
 )
 from ebook_converter.utils.localization import get_udc
diff --git a/ebook_converter/utils/fonts/scanner.py b/ebook_converter/utils/fonts/scanner.py
index 1e07936..4883acc 100644
--- a/ebook_converter/utils/fonts/scanner.py
+++ b/ebook_converter/utils/fonts/scanner.py
@@ -3,7 +3,7 @@ from collections import defaultdict
 from threading import Thread
 
 from ebook_converter import walk, prints, as_unicode
-from ebook_converter.constants import (config_dir, iswindows, isosx, plugins, DEBUG,
+from ebook_converter.constants_old import (config_dir, iswindows, isosx, plugins, DEBUG,
         isworker, filesystem_encoding)
 from ebook_converter.utils.fonts.metadata import FontMetadata, UnsupportedFont
 
diff --git a/ebook_converter/utils/formatter.py b/ebook_converter/utils/formatter.py
index ba13917..1307399 100644
--- a/ebook_converter/utils/formatter.py
+++ b/ebook_converter/utils/formatter.py
@@ -6,7 +6,7 @@ Created on 23 Sep 2010
 import re, string, traceback, numbers
 
 from ebook_converter import prints
-from ebook_converter.constants import DEBUG
+from ebook_converter.constants_old import DEBUG
 from ebook_converter.utils.formatter_functions import formatter_functions
 from ebook_converter.polyglot.builtins import error_message
 
diff --git a/ebook_converter/utils/formatter_functions.py b/ebook_converter/utils/formatter_functions.py
index 5cbf1ed..3078532 100644
--- a/ebook_converter/utils/formatter_functions.py
+++ b/ebook_converter/utils/formatter_functions.py
@@ -7,7 +7,7 @@ import inspect, re, traceback, numbers
 from math import trunc
 
 from ebook_converter import human_readable
-from ebook_converter.constants import DEBUG
+from ebook_converter.constants_old import DEBUG
 from ebook_converter.ebooks.metadata import title_sort
 from ebook_converter.utils.config import tweaks
 from ebook_converter.utils.titlecase import titlecase
diff --git a/ebook_converter/utils/icu.py b/ebook_converter/utils/icu.py
index 27f5643..fc2631e 100644
--- a/ebook_converter/utils/icu.py
+++ b/ebook_converter/utils/icu.py
@@ -3,7 +3,7 @@ import sys
 import unicodedata
 
 # Setup code {{{
-from ebook_converter.constants import plugins
+from ebook_converter.constants_old import plugins
 from ebook_converter.polyglot.builtins import cmp
 from ebook_converter.utils.config_base import tweaks
 
diff --git a/ebook_converter/utils/img.py b/ebook_converter/utils/img.py
index b9466c4..b65d943 100644
--- a/ebook_converter/utils/img.py
+++ b/ebook_converter/utils/img.py
@@ -12,7 +12,7 @@ from threading import Thread
 #from PyQt5.QtGui import QColor, QImage, QImageReader, QImageWriter, QPixmap, QTransform
 
 from ebook_converter import fit_image, force_unicode
-from ebook_converter.constants import iswindows, plugins
+from ebook_converter.constants_old import iswindows, plugins
 from ebook_converter.ptempfile import TemporaryDirectory
 from ebook_converter.utils.config_base import tweaks
 from ebook_converter.utils.filenames import atomic_rename
diff --git a/ebook_converter/utils/ipc/__init__.py b/ebook_converter/utils/ipc/__init__.py
index a431a12..1bbb0fb 100644
--- a/ebook_converter/utils/ipc/__init__.py
+++ b/ebook_converter/utils/ipc/__init__.py
@@ -5,10 +5,10 @@ import sys
 import threading
 
 from ebook_converter import force_unicode
-from ebook_converter.constants import filesystem_encoding
-from ebook_converter.constants import get_windows_username
-from ebook_converter.constants import islinux
-from ebook_converter.constants import iswindows
+from ebook_converter.constants_old import filesystem_encoding
+from ebook_converter.constants_old import get_windows_username
+from ebook_converter.constants_old import islinux
+from ebook_converter.constants_old import iswindows
 from ebook_converter.utils.filenames import ascii_filename
 
 
diff --git a/ebook_converter/utils/ipc/launch.py b/ebook_converter/utils/ipc/launch.py
index 1d05662..fae4234 100644
--- a/ebook_converter/utils/ipc/launch.py
+++ b/ebook_converter/utils/ipc/launch.py
@@ -1,7 +1,7 @@
 import subprocess, os, sys, time
 from functools import partial
 
-from ebook_converter.constants import isosx, isfrozen, filesystem_encoding
+from ebook_converter.constants_old import isosx, isfrozen, filesystem_encoding
 from ebook_converter.utils.config import prefs
 from ebook_converter.ptempfile import PersistentTemporaryFile, base_dir
 from ebook_converter.utils.serialize import msgpack_dumps
diff --git a/ebook_converter/utils/ipc/simple_worker.py b/ebook_converter/utils/ipc/simple_worker.py
index 744055a..52a89fc 100644
--- a/ebook_converter/utils/ipc/simple_worker.py
+++ b/ebook_converter/utils/ipc/simple_worker.py
@@ -3,7 +3,7 @@ from multiprocessing.connection import Client
 from threading import Thread
 from contextlib import closing
 
-from ebook_converter.constants import iswindows
+from ebook_converter.constants_old import iswindows
 from ebook_converter.utils.ipc import eintr_retry_call
 from ebook_converter.utils.ipc.launch import Worker
 from ebook_converter.utils.serialize import msgpack_loads, msgpack_dumps
diff --git a/ebook_converter/utils/iso8601.py b/ebook_converter/utils/iso8601.py
index d0cb8a1..3286c5a 100644
--- a/ebook_converter/utils/iso8601.py
+++ b/ebook_converter/utils/iso8601.py
@@ -2,7 +2,7 @@ from datetime import datetime
 
 from dateutil.tz import tzlocal, tzutc, tzoffset
 
-from ebook_converter.constants import plugins
+from ebook_converter.constants_old import plugins
 # speedup, err = plugins['speedup']
 # if not speedup:
     # raise RuntimeError(err)
diff --git a/ebook_converter/utils/lock.py b/ebook_converter/utils/lock.py
index 67d1c86..2d8a415 100644
--- a/ebook_converter/utils/lock.py
+++ b/ebook_converter/utils/lock.py
@@ -8,7 +8,7 @@ import tempfile
 import time
 from functools import partial
 
-from ebook_converter.constants import (
+from ebook_converter.constants_old import (
     __appname__, fcntl, filesystem_encoding, islinux, isosx, iswindows, plugins
 )
 from ebook_converter.utils.monotonic import monotonic
@@ -16,7 +16,7 @@ from ebook_converter.utils.monotonic import monotonic
 # speedup = plugins['speedup'][0]
 if iswindows:
     import msvcrt, win32file, pywintypes, winerror, win32api, win32event
-    from ebook_converter.constants import get_windows_username
+    from ebook_converter.constants_old import get_windows_username
     excl_file_mode = stat.S_IREAD | stat.S_IWRITE
 else:
     excl_file_mode = stat.S_IRUSR | stat.S_IWUSR | stat.S_IRGRP | stat.S_IROTH
diff --git a/ebook_converter/utils/monotonic.py b/ebook_converter/utils/monotonic.py
index d16d9e5..7db686c 100644
--- a/ebook_converter/utils/monotonic.py
+++ b/ebook_converter/utils/monotonic.py
@@ -1,7 +1,7 @@
 try:
     from time import monotonic
 except ImportError:
-    from ebook_converter.constants import plugins
+    from ebook_converter.constants_old import plugins
 
     monotonicp, err = plugins['monotonic']
     if err:
diff --git a/ebook_converter/utils/shared_file.py b/ebook_converter/utils/shared_file.py
index 995d6dd..67ccf6a 100644
--- a/ebook_converter/utils/shared_file.py
+++ b/ebook_converter/utils/shared_file.py
@@ -17,7 +17,7 @@ file before deleting it.
 import os, sys
 
 from ebook_converter.polyglot.builtins import reraise
-from ebook_converter.constants import iswindows, plugins
+from ebook_converter.constants_old import iswindows, plugins
 
 
 __license__ = 'GPL v3'