This table describes the release history of the email package, corresponding
to the version of Python that the package was released with. For purposes of
this document, when you see a note about change or added versions, these refer
to the Python version the change was made it, not the email package
version. This table also describes the Python compatibility of each version
of the package.
Python 2.2.0 to Python 2.2.1
no longer supported
Python 2.2.2+ and Python 2.3
Python 2.1 to 2.5
Python 2.3 to 2.5
Python 2.3 to 2.5
Here are the major differences between email version 4 and version 3:
All modules have been renamed according to PEP 8 standards. For
example, the version 3 module email.Message was renamed to
email.message in version 4.
A new subpackage email.mime was added and all the version 3
email.MIME* modules were renamed and situated into the
email.mime subpackage. For example, the version 3 module
email.MIMEText was renamed to email.mime.text.
Note that the version 3 names will continue to work until Python
The email.mime.application module was added, which contains the
Methods that were deprecated in version 3 have been removed. These
include Generator.__call__(), Message.get_type(),
Fixes have been added for RFC 2231 support which can change some of
the return types for Message.get_param() and friends. Under
some circumstances, values which used to return a 3-tuple now return
simple strings (specifically, if all extended parameter segments were
unencoded, there is no language and charset designation expected, so the
return type is now a simple string). Also, %-decoding used to be done
for both encoded and unencoded segments; this decoding is now done only
for encoded segments.
Here are the major differences between email version 3 and version 2:
The FeedParser class was introduced, and the Parser
class was implemented in terms of the FeedParser. All parsing
therefore is non-strict, and parsing will make a best effort never to
raise an exception. Problems found while parsing messages are stored in
the message's defect attribute.
All aspects of the API which raised DeprecationWarnings in
version 2 have been removed. These include the _encoder argument
to the MIMEText constructor, the Message.add_payload()
method, the Utils.dump_address_pair() function, and the
functions Utils.decode() and Utils.encode().
New DeprecationWarnings have been added to:
Message.get_main_type(), Message.get_subtype(), and
the strict argument to the Parser class. These are
expected to be removed in future versions.
Support for Pythons earlier than 2.3 has been removed.
Here are the differences between email version 2 and version 1:
The email.Header and email.Charset modules
have been added.
The pickle format for Message instances has changed.
Since this was never (and still isn't) formally defined, this
isn't considered a backward incompatibility. However if your
application pickles and unpickles Message instances, be
aware that in email version 2, Message
instances now have private variables _charset and
Several methods in the Message class have been
deprecated, or their signatures changed. Also, many new methods
have been added. See the documentation for the Message
class for details. The changes should be completely backward
The object structure has changed in the face of
message/rfc822 content types. In email
version 1, such a type would be represented by a scalar payload,
i.e. the container message's is_multipart() returned
false, get_payload() was not a list object, but a single
This structure was inconsistent with the rest of the package, so
the object representation for message/rfc822 content
types was changed. In email version 2, the container
does return True from is_multipart(), and
get_payload() returns a list containing a single
Note that this is one place that backward compatibility could
not be completely maintained. However, if you're already
testing the return type of get_payload(), you should be
fine. You just need to make sure your code doesn't do a
set_payload() with a Message instance on a
container with a content type of message/rfc822.
The Parser constructor's strict argument was
added, and its parse() and parsestr() methods
grew a headersonly argument. The strict flag was
also added to functions email.message_from_file()
Generator.__call__() is deprecated; use
Generator.flatten() instead. The Generator
class has also grown the clone() method.
The DecodedGenerator class in the
email.Generator module was added.
The intermediate base classes MIMENonMultipart and
MIMEMultipart have been added, and interposed in the
class hierarchy for most of the other MIME-related derived
The _encoder argument to the MIMEText constructor
has been deprecated. Encoding now happens implicitly based
on the _charset argument.
The following functions in the email.Utils module have
been deprecated: dump_address_pairs(),
decode(), and encode(). The following
functions have been added to the module:
encode_rfc2231(), and decode_params().
The non-public function email.Iterators._structure()