Email client

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Revision as of 20:51, 2 July 2019 by Gary (talk | contribs) (Incoming message handling)
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An email client (alternatively spelled e-mail client; commonly known as mail client; more formally known as mail user agent or MUA; hereinafter, the Client) is any digital construct that an end-user utilizes to compose, access, and/or manage his or her emails.

The Client can also refer to mail client software. More broadly, email software may refer to all the software utilized for the Clients, mail servers, or mail exchangers.


Functions

Communication

With regard to:
  • Outgoing messages, the Clients may be designed to:
    1. Accept requests from end-users to compose new messages.
    2. Analyze requests looking for their inconsistencies and/or missing data.
    3. Offer end-users to correct inconsistencies and/or add the missing data.
    4. Transfer messages to mail servers.
  • Stored messages, the Clients may be designed to:
    1. Accept requests from end-users to manage -- delete, arrange, label, classify -- stored messages.
    2. Offer end-users to confirm those changes that are setup as critical.
    3. Execute the requests -- delete, arrange, label, classify -- stored messages.
  • Incoming messages, the Clients may be designed to:
    1. Accept messages from mail servers.
    2. Analyze messages looking for their inconsistencies and/or missing data.
    3. Add information about the found inconsistencies and/or missing data to the messages. This information may further be used by mail clients to combat spam.
    4. Display messages to end-users.
On the one side, the Clients receive requests from and display the data to end-users. On the other side, the Clients communicate with mail servers in order to receive emails from and/or send emails to.

Mailbox management

Message composition

Encryption

Hosting

There are two major models of locating the Clients:

  1. On-premises: end-users may install the Clients on their devices; a common example would be an app running on one's cell phone. The POP3 protocol is commonly used for sending one's emails to and/or receiving from mail servers.
  2. Online: end-users may access the Clients that are hosted online, often, next to a mail server. The IMAP protocol is commonly used for accessing and/or managing one's emails online.

Software

General comparison

General comparison of the popular Clients
Category Features Evolution Outlook RoundCube Thunderbird Zimbra
Trivia Ownership OSS Proprietary OSS OSS OSS
Developer Community Microsoft Community Foundation Corporation
License GPL Unknown GPL MPL YPL-like
UI GUI (GTK) GUI GUI GUI (XUL) GUI
Latest release 3.32.2 2019 (16) 1.2.5 60.7.2 8.6.0
Date 05/08/2019 09/24/2018 04/28/2017 06/20/2019 12/15/2014
Introduction 2000 1997 2006 2003 2005
OS Windows No Yes Cross-platform Cross-platform Cross-platform
macOS No Yes
Linux UNIX-like No
BSD No
Unix No
Category Features Evolution Outlook RoundCube Thunderbird Zimbra

Communication protocols

Communication protocols supported by the popular Clients
Category Features Evolution Outlook RoundCube Thunderbird Zimbra
IMAP IMAP4 Yes Yes Yes Yes Yes
POP3 Fetch all messages Yes Yes Yes Yes Yes
Selected by filter No No No No No
Selected by user Yes No No No No
Communication protocols other than POP3 and IMAP SMTP Yes Yes Yes Yes Yes
NNTP Yes No No Yes No
EWS Plug-in Yes Unknown Extensible Unknown
IPv6 Unknown Yes Unknown Yes Unknown
MAPI Plug-in Yes Unknown Unknown Unknown
Category Features Evolution Outlook RoundCube Thunderbird Zimbra

Integration protocols

Integration protocols supported by the popular Clients
Category Features Evolution Outlook RoundCube Thunderbird Zimbra
RSS 0.91 Feeds No Unknown Unknown No Unknown
1.0 Feeds No Unknown Unknown No Unknown
2.0 Feeds No Yes Unknown Yes Yes
Integration protocols other than RSS IMSP No Yes Unknown Yes Yes
ACAP No Yes Unknown Yes Yes
ATOM Feeds No Yes Unknown Yes Yes
iCalendar Yes Yes Unknown Yes Yes
MAPI/RPC Yes Yes Unknown Yes Unknown
CalDAV Yes No Unknown Yes Unknown
CardDAV Yes No Plug-in Yes Unknown
Category Features Evolution Outlook RoundCube Thunderbird Zimbra

Access

Access features in the popular Clients
Category Features Evolution Outlook RoundCube Thunderbird Zimbra
LDAP v2 Yes Yes Yes Partial Yes
v3 Yes Unknown Yes Partial Yes
Regular authentication Login Yes Yes Yes Yes Yes
Plain Yes No Yes Yes Yes
CRAM-HMAC MD5 Yes No Yes Yes Yes
SHA1 No No Yes No Unknown
RIPEMD No No Unknown No Unknown
MD5 APOP Yes No Yes Yes Yes
DIGEST-MD5 Yes No Yes No Unknown
Other authentication MSN (NTLM) browser login Yes Yes Unknown Yes Unknown
Compuserve (RPA) No No Unknown No Unknown
Hardware token PKCS#11 No No Yes Yes Yes
Biometric No No Unknown No Unknown
SMTP Auth Yes Yes Yes Yes Yes
X.509 client certificate No No Unknown Yes Unknown
OAuth Unknown Unknown Unknown Yes Unknown
Category Features Evolution Outlook RoundCube Thunderbird Zimbra

Security

Security features in the popular Clients
Category Features Evolution Outlook RoundCube Thunderbird Zimbra
SSL/TLS support Secure POP3 SSL/TSL SSL SSL/TSL SSL/TSL SSL/TSL
Secure IMAP4 SSL/TSL SSL/TSL SSL/TSL SSL/TSL SSL/TSL
Secure SMTP SSL/TSL SSL/TSL SSL/TSL SSL/TSL SSL/TSL
Secure NNTP SSL/TSL Unknown No SSL/TSL SSL/TSL
Secure LDAP SSL/TSL Unknown SSL/TSL SSL SSL/TSL
SNI Unknown Unknown Unknown Yes Unknown
OCSP No Unknown Unknown Yes Unknown
CRL No Unknown Unknown Yes Unknown
PGP support inline Yes No Unknown Yes Unknown
PGP/MIME or OpenPGP Yes No Yes Yes No
S/MIME support protocol Yes Yes Yes Yes Unknown
OCSP Unknown Unknown Unknown Yes Unknown
CRL Unknown Yes Unknown Unknown Unknown
Certificates on tokens, smartcards support Unknown Yes Unknown Yes Unknown
Category Features Evolution Outlook RoundCube Thunderbird Zimbra

Incoming message handling

Management of incoming messages the popular Clients
Category Features Evolution Outlook RoundCube Thunderbird Zimbra
Filtering Local junk Yes Yes Yes Yes Yes
Server-side junk Unknown Yes Yes Yes Yes
Phishing No Yes Depends on antivirus Yes Depends on antivirus
Appearance HTML email Yes Yes Yes Yes Yes
UTF-8 support Yes Yes Yes Yes Yes
Image blocking Yes Yes Yes Yes Yes
Thread view Yes Yes Yes Yes Yes
Conversation view No Yes Unknown Yes Unknown
Native images preview jpeg Yes Yes Yes Yes Yes
gif Yes Yes Yes Yes Yes
bmp Yes Yes Yes Yes Yes
png Yes Yes Yes Yes Yes
Native documents preview txt Unknown Yes Yes Yes Unknown
pdf Unknown Plug-in Yes Yes Unknown
doc Unknown Yes Yes No Unknown
xls Unknown Yes Yes No Unknown
odt Unknown Yes Yes No Unknown
ods Unknown Yes Yes No Unknown
New mail notification ticker No Unknown Yes Unknown Unknown
tray icon Yes Yes No Yes Unknown
tooltip Yes Yes No Yes Unknown
sound Yes Yes Yes Yes Unknown
Category Features Evolution Outlook RoundCube Thunderbird Zimbra

Stored message handling

Integration protocols supported by the popular Clients
Category Features Evolution Outlook RoundCube Thunderbird Zimbra
Message (general) Bi-directional text support Yes Unknown Yes Unknown Unknown
Postpone/scheduled message sending Unknown Yes Unknown Yes Unknown
Label messages with colors Yes Yes Yes Yes Yes
with flag Yes Yes Yes Yes Yes
antidelete Unknown No Yes Unknown Yes
add note Unknown Yes Yes Unknown Yes
Reformat received messages edit headers (e.g., Subject) No Yes Unknown Plug-in Unknown
forced recode Unknown Unknown Unknown Unknown Unknown
IMAP Search Yes Yes Yes Yes Yes
IDLE Yes Yes Unknown Yes Yes
Folders Customizable interface Partial Yes Yes Yes Yes
Customizable keybindings Yes Yes Yes Unknown Yes
Fragmented messages Yes Unknown Unknown No Yes
Database search with regular expressions support Yes Unknown Unknown Unknown Yes
Indexed search Yes Yes Unknown Yes Yes
Search folders Yes Yes Yes Yes Yes
Database Message file format maildir, mbox, MH Proprietary IMAP Server mbox, maildir File system
Encrypted database No Yes Unknown No No
Virtual folders Yes Yes Unknown Yes Yes
Scheduled backup No Yes Unknown Unknown Yes
Category Features Evolution Outlook RoundCube Thunderbird Zimbra

Outgoing message handling

Integration protocols supported by the popular Clients
Category Features Evolution Outlook RoundCube Thunderbird Zimbra
Composing messages Spell checking Yes Yes Yes Yes Yes
Signatures Yes Yes Yes Yes Yes
Bottom-posts replies Unknown No Unknown Yes Unknown
Message templates new Yes Yes Yes Yes Yes
reply Yes Yes Yes Yes Yes
forward Yes Yes Yes Yes Yes
read confirmation Yes Yes Yes Yes Yes
save Yes No Yes Yes Yes
print Yes No Yes Yes Yes
Individual for Unknown Unknown Unknown Profile Any
Support in message templates scripts, programming languages JavaScript Unknown Unknown No Yes No
VBScript Unknown Unknown No Unknown No
PHP Scripts Unknown Unknown No Unknown No
Python Unknown Unknown No Unknown No
Regular expressions Unknown Unknown No Unknown No
Java Unknown Unknown No Unknown Unknown
Category Features Evolution Outlook RoundCube Thunderbird Zimbra

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