Version 2.1.0


  • TravisCI now runs tests against PyPy
  • Python 3.7 is now officially supported
  • Cleaned up server capability checks
  • Use TLS by default for interactive sessions


  • Support the QUOTA extension
  • Support for locating special folders (find_special_folder())
  • Document usage of client TLS certificates
  • Added documentation & example for parsing retrieved emails using the standard library email package.


  • Handle NIL values for INTERNALDATE

Version 2.0


  • Only use Python’s built-in TLS support (no more backports.ssl & pyOpenSSL)
  • Connections use SSL/TLS by default (ssl=True)
  • Drop imapclient.tls.create_default_context function. In case you were using it, you can use the method with the same name available in the built-in ssl module.
  • Logs are now handled by the Python logging module. The debug and log_file attributes are gone.
  • More precise exceptions available in imapclient.exceptions are raised when an error happens
  • imapclient.exceptions.ProtocolError is now raised when the reply from a remote server violates the IMAP protocol.
  • SEARCH exceptions now link to relevant documentation.
  • GMail labels are now strings instead of bytes in Python 3.
  • OAUTH v1 support removed.
  • has been simplified.
  • All non-library code moved out of the imapclient package.
  • Many documentation improvements.


  • Connection and read/write operations timeout can now be distinct, using imapclient.SocketTimeout namedtuple as timeout parameter.
  • A context manager is introduced to automatically close connections to remote servers.
  • EXPUNGE by ID support.
  • ENABLE support.
  • UNSELECT support.
  • Atomically move messages to another folder using the MOVE extension (RFC 6851)
  • New welcome property to allow access to IMAP server greeting.


  • GMail labels using international characters are now handled properly.
  • Don’t use locale dependent formatting in datetime_to_INTERNAL_DATE().
  • Quote empty strings to prevent syntax errors while SEARCHing for zero-length strings.
  • Handle address without mailbox name or host in Address namedtuple.
  • Avoid asserts in response parsing codes to allow graceful recovery.
  • Prevent logging of IMAP passwords.

Python compatibility

Support for Python 2.6 and 3.3 is removed in this release.

This version supports Python 2.7, 3.4, 3.5 and 3.6. We officially support the latest release of each series.

Version 1.1.0


  • Search now supports nested criteria so that more complex criteria can be expressed. IMAPClient will add parentheses in the right place.
  • PLAIN authentication support (via plain_login method)
  • unselect_folder() method, for servers with the UNSELECT capability (#200)
  • Add ENABLE support (#136)
  • UID EXPUNGE support (#287)


  • the mock package is no longer installed by default (just as a test dependency)
  • handle NIL date values in INTERNALDATE
  • add silent option to all flags methods (improves performance by avoiding unnecessary parsing)
  • simplify Gmail label functionality
  • folder_status is more robust
  • various livetest reliability improvements


  • don’t quote search criteria when sent as IMAP literals. Fixes #249.
  • Modified UTF-7 encoding function had quirks in its original algorithm, leading to incorrect encoded output in some cases. The algorithm, described in RFC 3501, has been reimplemented to fix #187 and is better documented.
  • use fixed month names when formatting INTERNALDATES (don’t rely on locale)
  • handle address without mailbox name or host in Address namedtuple. Fixes #242.
  • Use cryptography < 2.0 on Python 3.3. Fixes #305.

Version 1.0.2


  • Documented the livetest/interact INI file format.
  • Documented handling of RFC2822 group syntax.


  • Explicitly check that the required pyOpenSSL version is installed
  • Start testing against Python 3.5
  • Update doc links from to
  • Rearranged README so that project essentials are right at the top.


  • Allow installation from alternate directories

Version 1.0.1


  • Minimum backports.ssl dependency is now 0.0.9 (an important performance issue was addressed)
  • setuptools 18.8.1 now used due to strange zip file error for 17.1


  • Unit test for version strings were updated to now always include the patch version.
  • Fresh capabilities now retrieved between STARTTLS and authentication (#195).

Version 1.0.0

Enhanced TLS support [API]

The way that IMAPClient establishes TLS/SSL connections has been completely reworked. By default IMAPClient will attempt certificate verification, certificate hostname checking, and will not use known-insecure TLS settings and protocols. In addition, TLS parameters are now highly configurable.

By leveraging pyOpenSSL and backports.ssl, all Python versions supported by IMAPClient enjoy the same TLS functionality and API.

These packages mean that IMAPClient now has a number of new dependencies. These should be installed automatically as required but there will no doubt be complications.

Compatibility breaks:

  1. Due to lack of support in some of the dependent libraries, IMAPClient no longer supports Python 3.2.
  2. The passthrough keyword arguments that the IMAPClient constructor took in past versions are no longer accepted. These were in place to provide access to imaplib’s SSL arguments which are no longer relevant. Please pass a SSL context object instead.
  3. When using the default SSL context that IMAPClient creates (recommended), certificate verification is enabled. This means that IMAPClient connections to servers that used to work before, may fail now (especially if a self-signed certificate is used by the server). Refer to the documentation for details of how to supply alternate CA certificates or disable verification.
  4. There are some new exceptions that might be raised in response to network issues or TLS protocol failures. Refer to the Exceptions section of the manual for more details.

Please refer to the “TLS/SSL” section of the manual for more details on all of the above.

Many thanks to Chris Arndt and Marc-Antoine Parent for their input into these TLS improvements.

STARTTLS support [NEW]

When the server supports it, IMAPClient can now establish an encrypted connection after initially starting with an unencrypted connection using the STARTTLS command. The starttls method takes an SSL context object for controlling the parameters of the TLS negotiation.

Many thanks to Chris Arndt for his extensive initial work on this.

More robust criteria handling for search, sort and thread [API]

IMAPClient’s methods that accept search criteria (search, sort, thread, gmail_search) have been changed to provide take criteria in a more straightforward and robust way. In addition, the way the charset argument interacts with search criteria has been improved. These changes make it easier to pass search criteria and have them handled correctly but unfortunately also mean that small changes may be required to existing code that uses IMAPClient.

Search criteria

The preferred way to specify criteria now is as a list of strings, ints and dates (where relevant). The list should be flat with all the criteria parts run together. Where a criteria takes an argument, just provide it as the next element in the list.

Some valid examples:['DELETED'])['NOT', 'DELETED'])['FLAGGED', 'SUBJECT', 'foo', 'BODY', 'hello world'])['NOT', 'DELETED', 'SMALLER', 1000])['SINCE', date(2006, 5, 3)])

IMAPClient will perform all required conversion, quoting and encoding. Callers do not need to and should not attempt to do this themselves. IMAPClient will automatically send criteria parts as IMAP literals when required (i.e. when the encoded part is 8-bit).

Some previously accepted ways of passing search criteria will not work as they did in previous versions of IMAPClient. Small changes will be required in these cases. Here are some examples of how to update code written against older versions of IMAPClient:['NOT DELETED'])    # Before['NOT', 'DELETED']) # After['TEXT "foo"'])     # Before['TEXT', 'foo'])    # After (IMAPClient will add the quotes)['DELETED', 'TEXT "foo"'])    # Before['DELETED', 'TEXT', 'foo'])   # After['SMALLER 1000'])    # Before['SMALLER', 1000])   # After

It is also possible to pass a single string as the search criteria. IMAPClient will not attempt quoting in this case, allowing the caller to specify search criteria at a lower level. Specifying criteria using a sequence of strings is preferable however. The following examples (equivalent to those further above) are valid:'DELETED')'NOT DELETED')'FLAGGED SUBJECT "foo" BODY "hello world"')'NOT DELETED SMALLER 1000')'SINCE 03-May-2006')

Search charset

The way that the search charset argument is handled has also changed.

Any unicode criteria arguments will now be encoded by IMAPClient using the supplied charset. The charset must refer to an encoding that is capable of handling the criteria’s characters or an error will occur. The charset must obviously also be one that the server supports! (UTF-8 is common)

Any criteria given as bytes will not be changed by IMAPClient, but the provided charset will still be passed to the IMAP server. This allows already encoding criteria to be passed through as-is. The encoding referred to by charset should match the actual encoding used for the criteria.

The following are valid examples:['TEXT', u'\u263a'], 'utf-8')         # IMAPClient will apply UTF-8 encoding[b'TEXT', b'\xe2\x98\xba'], 'utf-8')  # Caller has already applied UTF-8 encoding

The documentation and tests for search, gmail_search, sort and thread has updated to account for these changes and have also been generally improved.

Socket timeout support [NEW]

IMAPClient now accepts a timeout at creation time. The timeout applies while establishing the connection and for all operations on the socket connected to the IMAP server.

Semantic versioning

In order to better indicate version compatibility to users, IMAPClient will now strictly adhere to the Semantic Versioning scheme.

Performance optimisation for parsing message id lists

A short circuit is now used when parsing a list of message ids which greatly speeds up parsing time.


  • Perform quoting of Gmail labels. Thanks to Pawel Sz for the fix.
  • The type of the various flag constants was fixed. Thanks to Thomi Richards for pointing this out.
  • Now using mock 1.3.0. Thanks to Thomi Richards for the patch.
  • Fixed handling of very long numeric only folder names. Thanks to Paweł Gorzelany for the patch.
  • The default charset for gmail_search is now UTF-8. This makes it easier to use any unicode string as a search string and is safe because Gmail supports UTF-8 search criteria.
  • PEP8 compliance fixed (except for some occasional long lines)
  • Added a “shutdown” method.
  • The embedded six package has been removed in favour of using an externally installed instance.
  • Fixed handling of literals in STATUS responses.
  • Only use the untagged post-login CAPABILITY response once (if sent by server).
  • Release history made part of the main documentation.
  • Clarified how message ids work in the docs.
  • Livetest infrastructure now works with Yahoo’s OAUTH2
  • Fixed bytes handling in Address.__str__

Version 0.13

Added support for the ID command [NEW]

As per RFC2971. Thanks to Eben Freeman from Nylas.

Fix exception with NIL address in envelope address list

Thanks to Thomas Steinacher for this fix.

Fixed handling of NIL in SEARCH response

Fixed a regression in the handling of NIL/None SEARCH responses. Thanks again to Thomas Steinacher.

Date parsing fixes

Don’t traceback when an unparsable date is seen in ENVELOPE responses. None is returned instead.

Support quirky timestamp strings which use dots for the time separator.

Removed horrible INTERNALDATE parsing code (use parse_to_datetime instead).

datetime_to_imap has been moved to the datetime_util module and is now called datetime_to_INTERNALDATE. This will only affect you in the unlikely case that you were importing this function out of the IMAPClient package.


  • The docs for various IMAPClient methods, and the HACKING.rst file have been updated.
  • CONDSTORE live test is now more reliable (especially when running against Gmail)

Version 0.12

Fixed unicode handling [API CHANGE]

During the work to support Python 3, IMAPClient was changed to do return unicode for most responses. This was a bad decision, especially because it effectively breaks content that uses multiple encodings (e.g. RFC822 responses). This release includes major changes so that most responses are returned as bytes (Python 3) or str (Python 2). This means that correct handling of response data is now possible by code using IMAPClient.

Folder name handling has also been cleaned up as part of this work. If the folder_encode attribute is True (the default) then folder names will always be returned as unicode. If folder_encode is False then folder names will always be returned as bytes/strs.

Code using IMAPClient will most likely need to be updated to account these unicode handling changes.

Many thanks to Inbox (now Nilas, for sponsoring this work.

Extra __init__ keyword args are passed through [NEW]

Any unused keyword arguments passed to the IMAPClient initialiser will now be passed through to the underlying imaplib IMAP4, IMAP4_SSL or IMAP4_stream class. This is specifically to allow the use of imaplib features that control certificate validation (if available with the version of Python being used).

Thanks to Chris Arndt for this change.

MODSEQ parts in SEARCH responses are now handled

If the CONDSTORE extension is supported by a server and a MODSEQ criteria was used with search(), a TypeError could occur. This has now been fixed and the MODSEQ value returned by the server is now available via an attribute on the returned list of ids.

Minor Changes

  • Small tweaks to support Python 3.4.
  • The deprecated get_folder_delimiter() method has been removed.
  • More control over OAUTH2 parameters. Thanks to Phil Peterson for this.
  • Fixed livetest/interact OAUTH handling under Python 3.

Version 0.11.1

  • Close folders during livetest cleanup so that livetests work with newer Dovecot servers (#131)

Version 0.11

Support for raw Gmail searching [NEW]

The new gmail_search methods allows direct Gmail queries using the X-GM-RAW search extension. Thanks to John Louis del Rosario for the patch.


ENVELOPE FETCH responses are now returned as Envelope instances. These objects are namedtuples providing convenient attribute and positional based access to envelope fields. The Date field is also now converted to a datetime instance.

As part of this change various date and time related utilities were moved to a new module at imapclient.datetime_util.

Thanks to Naveen Nathan for the work on this feature.

Correct nested BODYSTRUCTURE handling [API CHANGE]

BODY and BODYSTRUCTURE responses are now processed recusively so multipart sections within other multipart sections are returned correctly. This also means that each the part of the response now has a is_multipart property available.

NOTE: code that expects the old (broken) behaviour will need to be updated.

Thanks to Brandon Rhodes for the bug report.

SELECT response bug fix

Handle square brackets in flags returned in SELECT response. Previously these would cause parsing errors. Thanks to Benjamin Morrise for the bug report.

Minor Changes

Copyright date update for 2014.

Version 0.10.2

Switch back to setuptools now that distribute and setuptools have merged back. Some users were reporting problems with distribute and the newer versions of setuptools.

Version 0.10.1

Fixed regressions in several cases when binary data (i.e. normal strings under Python 2) are used as arguments to some methods. Also refactored input normalisation functions somewhat.

Fixed buggy method for extracting flags and Gmail labels from STORE responses.

Version 0.10

Python 3 support (#22) [API CHANGE]

Python 3.2 and 3.3 are now officially supported. This release also means that Python versions older than 2.6 are no longer supported.

A single source approach has been used, with no conversion step required.

A big thank you to Mathieu Agopian for his massive contribution to getting the Python 3 port finished. His changes and ideas feature heavily in this release.

IMPORTANT: Under Python 2, all strings returned by IMAPClient are now returned as unicode objects. With the exception of folder names, these unicode objects will only contain characters in the ASCII range so this shouldn’t break existing code, however there is always a chance that there will be a problem. Please test your existing applications thoroughly with this verison of IMAPClient before deploying to production situations.

Minor Changes

  • “python test” now runs the unit tests
  • Mock library is now longer included (listed as external test dependency)
  • live tests that aren’t UID related are now only run once
  • live tests now perform far less logins to the server under test
  • Unit tests can now be run for all supported Python versions using tox.
  • Improved documentation regarding working on the project.
  • Many documentation fixes and improvements.

Minor Bug Fixes

  • HIGHESTMODSEQ in SELECT response is now parsed correctly
  • Fixed daylight saving handling in FixedOffset class
  • Fixed –port command line bug in imapclient.interact when SSL connections are made.

Version 0.9.2

THREAD support [NEW]

The IMAP THREAD command is now supported. Thanks to Lukasz Mierzwa for the patches.

Enhanced capability querying [NEW]

Previously only the pre-authentication server capabilities were returned by the capabilities() method. Now, if the connection is authenticated, the post-authentication capabilities will be returned. If the server sent an untagged CAPABILITY response after authentication, that will be used, avoiding an unnecessary CAPABILITY command call.

All this ensures that the client sees all available server capabilities.

Minor Features

  • Better documentation for contributers (see HACKING file)
  • Copyright date update for 2013.

Version 0.9.1

Stream support [NEW]

It is now possible to have IMAPClient run an external command to establish a connection to the IMAP server via a new stream keyword argument to the initialiser. This is useful for exotic connection or authentication setups. The host argument is used as the command to run.

Thanks to Dave Eckhardt for the original patch.

OAUTH2 Support [NEW]

OAUTH2 authentication (as supported by Gmail’s IMAP) is now available via the new oauth2_login method. Thanks to Zac Witte for the original patch.

livetest now handles Gmail’s new message handling

Gmail’s IMAP implementation recently started requiring a NOOP command before new messages become visible after delivery or an APPEND. The livetest suite has been updated to deal with this.

Version 0.9

Gmail Label Support

New methods have been added for interacting with Gmail’s label API: get_gmail_labels, add_gmail_labels, set_gmail_labels, remove_gmail_labels. Thanks to Brian Neal for the patches.

Removed Code Duplication (#9)

A signficant amount of duplicated code has been removed by abstracting out common command handling code. This will make the Python 3 port and future maintenance easier.

livetest can now be run against non-dummy accounts (#108)

Up until this release the tests in imapclient.livetest could only be run against a dummy IMAP account (all data in the account would be lost during testing). The tests are now limited to a sub-folder created by the tests so it is ok to run them against an account that contains real messages. These messages will be left alone.

Minor Features

  • Don’t traceback when an IMAP server returns a all-digit folder name without quotes. Thanks to Rhett Garber for the bug report. (#107)
  • More tests for ACL related methods (#89)
  • More tests for namespace()
  • Added test for read-only select_folder()

Minor Bug Fixes

  • Fixed rename live test so that it uses folder namespaces (#100).
  • Parse STATUS responses robustly - fixes folder_status() with MS Exchange.
  • Numerous livetest fixes to work around oddities with the MS Exchange IMAP implementation.

Version 0.8.1

  • IMAPClient wasn’t installing on Windows due to an extra trailing slash in (#102). This is a bug in distutils.
  • was fixed so that the main documentation index file is included the source distribution.
  • was updated to the 0.6.24 version.
  • This release also contains some small documentation fixes.

Version 0.8

OAUTH Support (#54) [NEW]

OAUTH authentication is now supported using the oauth_login method. This requires the 3rd party oauth2 package is installed. Thanks to Johannes Heckel for contributing the patch to this.

IDLE Support (#50) [NEW]

The IDLE extension is now supported through the new idle(), idle_check() and idle_done() methods. See the example in imapclient/examples/

NOOP Support (#74) [NEW]

The NOOP command is now supported. It returns parsed untagged server responses in the same format as idle_check() and idle_done().

Sphinx Based Docs (#5) [NEW]

Full documentation is now available under doc/html in the source distribution and at online.

Added rename_folder (#77) [NEW]

Renaming of folders was an obvious omission!

Minor Features

  • can now read INI files (#66)
  • can now embed shells from ipython 0.10 and 0.11 (#98)
  • and are now inside the imapclient package so they can be used even when IMAClient has been installed from PyPI (#82)
  • Added “debug” propety and setting of a log file (#90)
  • “normalise_times” attribute allows caller to select whether datetimes returned by fetch() are native or not (#96) (Thanks Andrew Scheller)
  • Added imapclient.version_info - a tuple that contains the IMAPClient version number broken down into it’s parts.

Minor Bug Fixes

  • getacl() was using wrong lexing class (#85) (Thanks josephhh)
  • Removed special handling for response tuples without whitespace between them. Post-process BODY/BODYSTRUCTURE responses instead. This should not affect the external API. (#91) (Thanks daishi)
  • Fix incorrect msg_id for UID fetch when use_uid is False (#99)

Version 0.7

BODY and BODYSTRUCTURE parsing fixes (#58) [API CHANGE]

The response values for BODY and BODYSTRUCTURE responses may include a sequence of tuples which are not separated by whitespace. These should be treated as a single item (a list of multiple arbitrarily nested tuples) but IMAPClient was treating them as separate items. IMAPClient now returns these tuples in a list to allow for consistent parsing.

A BODYSTRUCTURE response for a multipart email with 2 parts would have previously looked something like this:

(('text', 'html', ('charset', 'us-ascii'), None, None, 'quoted-printable', 55, 3),
 ('text', 'plain', ('charset', 'us-ascii'), None, None, '7bit', 26, 1),
 'mixed', ('boundary', '===============1534046211=='))

The response is now returned like this:

   ('text', 'html', ('charset', 'us-ascii'), None, None, 'quoted-printable', 55, 3),
   ('text', 'plain', ('charset', 'us-ascii'), None, None, '7bit', 26, 1)
 'mixed', ('boundary', '===============1534046211=='))

The behaviour for single part messages is unchanged. In this case the first element of the tuple is a string specifying the major content type of the message (eg “text”).

An is_multipart boolean property now exists on BODY and BODYSTRUCTURE responses to allow the caller to easily determine whether the response is for a multipart message.

Code that expects the previous response handling behaviour needs to be updated.

Live tests converted to use unittest2 (#4) now uses the unittest2 package to run the tests. This provides much more flexibility that the custom approach that was used before. Dependencies between tests are gone - each test uses a fresh IMAP connection and is preceeded by the same setup.

unittest2.main() is used to provide a number of useful command line options and the ability to run a subset of tests.

IMAP account parameters are now read using a configuration file instead of command line arguments. See livetest-sample.ini for an example.

Added NAMESPACE support (#63) [API CHANGE]

namespace() method added and get_folder_delimiter() has been deprecated.

Added support for FETCH modifiers (#62) [NEW]

The fetch method now takes optional modifiers as the last argument. These are required for extensions such as RFC 4551 (conditional store). Thanks to Thomas Jost for the patch.

Version 0.6.2

Square brackets in responses now parsed correctly (#55)

This fixes response handling for FETCH items such as BODY[HEADER.FIELDS (from subject)].

Example moved (#56)

The example has been moved to imapclient/examples directory and is included when the IMAPClient is installed from PyPI.

Distribute (#57)

The project is now packaged using Distribute instead of setuptools. There should be no real functional change.

Version 0.6.1

Python SSL bug patch

Automatically patch a bug in imaplib which can cause hangs when using SSL (Python Issue 5949). The patch is only applied when the running Python version is known to be affected by the problem.

Doc update

Updated the README to better reflect the current state of the project.

Version 0.6

New response parser (#1, #45)

Command response lexing and parsing code rewritten from stratch to deal with various bugs that surfaced when dealing with more complex responses (eg. BODYSTRUCTURE and ENVELOPE). This change also fixes various problems when interacting with Gmail and MS Exchange.

XLIST extension support (#25) [NEW]

Where the server supports it, xlist_folders() will return a mapping of various common folder names to the actual server folder names. Gmail’s IMAP server supports this.

Added COPY command support (#36) [NEW]

New copy() method.

Added [NEW]

A script for interactive IMAPClient sessions. Useful for debugging and exploration. Uses IPython if installed.

Full SELECT response (#24) [API CHANGE]

select_folder() now returns a dictionary with the full (parsed) SELECT command response instead of just the message count.

Full list responses (#24) [API CHANGE]

The return value from list_folders(), list_sub_folders() and xlist_folders() now include the IMAP folder flags and delimiter.

Folder name character encoding (#21) [API CHANGE]

Bytes that are greater than 0x7f in folder names are will cause an exception when passed to methods that accept folder name arguments because there is no unambigous way to handle these. Callers should encode such folder names to unicode objects first.

Folder names are now always returned as unicode objects.

Message sequence number now always returned in FETCH responses

Fetch responses now include a “SEQ” element which gives the message (non-UID) sequence number. This allows for easy mapping between UIDs and standard sequence IDs.

Folder name handling fixes (#28, #42)

Various folder name handling bugs fixed.

Version 0.5.2

Folder name quoting and escaping fixes (#28)

Correctly handle double quotes and backslashes in folder names when parsing LIST and LSUB responses.

Fixed fetch literal handling (#33)

Fixed problem with parsing responses where a literal followed another literal.

Version 0.5.1

License change

Changed license from GPL to new BSD.

Version 0.5

SSL support

Support for SSL based connections by passing ssl=True when constructing an IMAPClient instance.

Transparent folder encoding

Folder names are now encoded and decoded transparently if required (using modified UTF-7). This means that any methods that return folder names may return unicode objects as well as normal strings [API CHANGE]. Additionally, any method that takes a folder name now accepts unicode object too. Use the folder_encode attribute to control whether encode/decoding is performed.

Unquoted folder name handling fix

Unquoted folder names in server responses are now handled correctly. Thanks to Neil Martinsen-Burrell for reporting this bug.

Fixed handling of unusual characters in folder names

Fixed a bug with handling of unusual characters in folder names.

Timezone handling [API CHANGE]

Timezones are now handled correctly for datetimes passed as input and for server responses. This fixes a number of bugs with timezones. Returned datetimes are always in the client’s local timezone.

More unit tests

Many more unit tests added, some using Michael Foord’s excellent (