Microsoft Outlook

Microsoft Outlook is a personal information manager from Microsoft, available as a part of the Microsoft Office suite. Although often used mainly as an email application, it also includes a calendar, task manager, contact manager, note taking, journal, and web browsing.

It can be used as a stand-alone application, or can work with Microsoft Exchange Server and Microsoft SharePoint Server for multiple users in an organization, such as shared mailboxes and calendars, Exchange public folders, SharePoint lists, and meeting schedules. Microsoft has also released mobile applications for most mobile platforms, including iOS and Android. Developers can also create their own custom software that works with Outlook and Office components using Microsoft Visual Studio.[6] In addition, Windows Phone devices can synchronize almost all Outlook data to Outlook Mobile.

Versions
Microsoft Outlook has replaced Microsoft's previous scheduling and mail programs, Schedule+ and Exchange Client.

Perpetual versions of Microsoft Outlook include: Outlook 98 and Outlook 2000 offer two configurations:
 * Internet Mail Only or IMO mode: A lighter application mode with specific emphasis on POP3 accounts and IMAP accounts and including a lightweight Fax application.
 * Corporate Workgroup or CW mode: A full MAPI client with specific emphasis on Microsoft Exchange accounts.

Outlook 2002
Outlook 2002 introduced the following new features:[13]
 * AutoComplete for email addresses
 * Colored categories for calendar items
 * Group schedules
 * Hyperlink support in email subject lines
 * Native support for Outlook.com (formerly Hotmail)
 * Improved search functionality including the ability to stop a search and resume it later
 * Lunar calendar support
 * MSN Messenger integration
 * Performance improvements[14]
 * Preview pane improvements including the ability to open hyperlinks; respond to meeting requests; and display email properties without opening a message
 * Reminder window that consolidates all reminders for appointments and tasks in a single view
 * Retention policies for documents and email
 * Security improvements including the automatic blocking of potentially unsafe attachments and of programmatic access to information in Outlook
 * SP1 introduced the ability to view all non-digitally signed email or unencrypted email as plain text[15]
 * SP2 allows users to—through the Registry—prevent the addition of new email accounts or the creation of new Personal Storage Tables[16]
 * SP3 updates the object model guard security for applications that access messages and other items[17]
 * Smart tags when Word is configured as the default email editor

Outlook 2003
Outlook 2003 introduced the following new features:[18]
 * AutoComplete suggestions for a single character
 * Cached Exchange mode
 * Colored (quick) flags
 * Desktop Alert
 * Email filtering to combat spam
 * Images in HTML mail are blocked by default to prevent spammers from determining whether an email address is active via web beacon[19]
 * SP1 introduced the ability to block email based on country code top-level domains[20]
 * SP2 introduced anti-phishing functionality that automatically disables hyperlinks present in spam[21]
 * Expandable distribution lists
 * Information rights management
 * Intrinsic support for tablet PC functionality (e.g., handwriting recognition)
 * Reading pane
 * Search folders
 * Unicode support

Outlook 2007
The main Outlook 2007 interface with its menus and toolbars.

Outlook 2007 with options for text message composition. The left-hand side depicts a preview of how the message will appear on the recipient's phone.

Features that debuted in Outlook 2007 include:[22]
 * Attachment preview, with which the contents of attachments can be previewed before opening
 * Supported file types include Excel, PowerPoint, Visio, and Word files. If Outlook 2007 is installed on Windows Vista, then audio and video files can be previewed. If a compatible PDF reader such as Adobe Acrobat 8.1 is installed, PDF files can also be previewed.[23]
 * Auto Account Setup, which allows users to enter a username and password for an email account without entering a server name, port number, or other information
 * Calendar sharing improvements including the ability to export a calendar as an HTML file—for viewing by users without Outlook—and the ability to publish calendars to an external service (e.g., Office Web Apps) with an online provider (e.g., Microsoft account)
 * Colored categories with support for user roaming, which replace colored (quick) flags introduced in Outlook 2003[24]
 * Improved email spam filtering and anti-phishing features
 * Postmark intends to reduce spam by making it difficult and time consuming to send it
 * Information rights management improvements with Windows Rights Management Services and managed policy compliance integration with Exchange Server 2007
 * Japanese Yomi name support for contacts
 * Multiple calendars can be overlaid with one another to assess details such as potential scheduling conflicts
 * Ribbon (Office Fluent) interface
 * Outlook Mobile Service support, which allowed multimedia and SMS text messages to be sent directly to mobile phones[25]
 * Instant search through Windows Search, an index-based desktop search platform
 * Instant search functionality is also available in Outlook 2002 and Outlook 2003 if these versions are installed alongside Windows Search[26]
 * Integrated RSS aggregation
 * Support for Windows SideShow with the introduction of a calendar gadget[27]
 * To-Do Bar that consolidates calendar information, flagged email, and tasks from OneNote 2007, Outlook 2007, Project 2007, and Windows SharePoint Services 3.0 websites within a central location.
 * The ability to export items as PDF or XPS files
 * Unified messaging support with Exchange Server 2007 with features such as missed call notifications, and voicemail with voicemail preview with Windows Media Player[27]
 * Word 2007 replaces Internet Explorer as the default viewer for HTML email[24]

Outlook 2010
Features that debuted in Outlook 2010 include:[28]
 * Additional command-line switches
 * An improved conversation view that groups messages based on different criteria regardless of originating folders
 * IMAP messages are sent to the Deleted Items folder, eliminating the need to mark messages for future deletion
 * Notification when email is about to be sent without a subject
 * Quick Steps, individual collections of commands that allow users to perform multiple actions simultaneously
 * Ribbon interface in all views
 * Search Tools contextual tab on the ribbon that appears when performing searches and that includes basic or advanced criteria filters
 * Social Connector to connect to various social networks and aggregate appointments, contacts, communication history, and file attachments
 * Spell check in additional areas of the user interface
 * Support for multiple Exchange accounts in a single Outlook profile
 * The ability to schedule a meeting with a contact by replying to an email message
 * To-Do Bar enhancements including visual indicators for conflicts and unanswered meeting requests
 * Voice mail transcripts for Unified Messaging communications
 * Zooming user interface for calendar and mail views

Outlook 2013
Features that debuted in Outlook 2013, which was released on January 29, 2013, include:
 * Attachment reminder
 * Exchange ActiveSync(EAS)
 * Add-in resiliency
 * Cached Exchange mode improvements
 * IMAP improvements
 * Outlook data file(.ost) compression
 * People hub
 * Startup performance improvements

Outlook 2016
Features that debuted in Outlook 2016, include:[29]
 * Attachment link to cloud resource
 * Groups redesign
 * Search cloud
 * Clutter Folder
 * Email Address Internationalization
 * Scalable Vector Graphics

Outlook 2019
Included with Microsoft Office 2019.

Outlook 2021
Included with Microsoft Office 2021.

Macintosh
Microsoft also released several versions of Outlook for classic Mac OS, though it was only for use with Exchange servers. It was not provided as a component of Microsoft Office for Mac, but instead made available to users from administrators or by download. The final version was Outlook for Mac 2001, which was fairly similar to Outlook 2000 and 2002 apart from being exclusively for Exchange users.

Microsoft Entourage was introduced as an Outlook-like application for Mac OS in Office 2001, but it lacked Exchange connectivity. Partial support for Exchange server became available natively in Mac OS Xwith Entourage 2004 Service Pack 2. Entourage is not directly equivalent to Outlook in terms of design or operation; rather, it is a distinct application which has several overlapping features including Exchange client capabilities. Somewhat improved Exchange support was added in Entourage 2008 Web Services Edition.

Microsoft Outlook for Mac 2011

Entourage was replaced by Outlook for Mac 2011, which features greater compatibility and parity with Outlook for Windows than Entourage offered. It is the first native version of Outlook for macOS.

Outlook 2011 initially supported Mac OS X's Sync Services only for contacts, not events, tasks or notes. It also does not have a Project Manager equivalent to that in Entourage.[30] With Service Pack 1 (v 14.1.0), published on April 12, 2011, Outlook can now sync calendar, notes and tasks with Exchange 2007 and Exchange 2010.

On October 31, 2014, Microsoft released Outlook for Mac (v15.3 build 141024) with Office 365 (a software as a service licensing program that makes Office programs available as soon as they are developed). Outlook for Mac 15.3 improves upon its predecessors with:[31]
 * Better performance and reliability as a result of a new threading model and database improvements.
 * A new modern user interface with improved scrolling and agility when switching between Ribbon tabs.
 * Online archive support for searching Exchange (online or on-premises) archived mail.
 * Master Category List support and enhancements delivering access to category lists (name and color) and sync between Mac, Microsoft Windows and OWA clients.
 * Office 365 push email support for real-time email delivery.
 * Faster first-run and email download experience with improved Exchange Web Services syncing.[31]

Outlook for phones and tablets
In January 2015, Microsoft released Outlook for phones and for tablets (v1.3 build) with Office 365.[32] This was the first Outlook for these platforms with email, calendar, and contacts.

HTML rendering
Outlook 2007 was the first Outlook to switch from Internet Explorer's rendering engine to Microsoft Word 2007. This means HTML and CSS items not handled by Word are no longer supported. On the other hand, HTML messages composed in Word look as they appeared to the author.[33] This affects publishing newsletters and reports, because they frequently use intricate HTML and CSS to form their layout. For example, forms can no longer be embedded in email.

Support of CSS properties and HTML attributes
Outlook for Windows has very limited CSS support compared to various other e-mail clients. Neither CSS1 (1996) nor CSS2 (1998) specifications are fully implemented and many CSS properties can only to be used with certain HTML elements for the desired effect.[34] Some HTML attributes help achieve proper rendering of e-mails in Outlook, but most of these attributes are already deprecated in the HTML 4.0 specifications (1997).[35] In order to achieve the best compatibility with Outlook, most HTML e-mails are created using multiple boxed tables, as the table element and its sub-elements support the width and height property in Outlook. No improvements have been made towards a more standards-compliant email client since the release of Outlook 2007.[36]

Transport Neutral Encapsulation Format
Main article: Transport Neutral Encapsulation Format

Outlook and Exchange Server internally handle messages, appointments and items as objects in a data model which is derived from the old proprietary Microsoft Mail system, the Rich Text Format from Microsoft Word and the complex OLE general data model.[37] When these programs interface with other protocols such as the various Internet and X.400 protocols, they try to map this internal model onto those protocols in a way that can be reversed if the ultimate recipient is also running Outlook or Exchange.[38]

This focus on the possibility that emails and other items will ultimately be converted back to Microsoft Mail format is so extreme that if Outlook/Exchange cannot figure out a way to encode the complete data in the standard format, it simply encodes the entire message/item in a proprietary binary format called Transport Neutral Encapsulation Format (TNEF) and sends this as an attached file (usually named "winmail.dat") to an otherwise incomplete rendering of the mail/item. If the recipient is Outlook/Exchange it can simply discard the incomplete outer message and use the encapsulated data directly, but if the recipient is any other program, the message received will be incomplete because the data in the TNEF attachment will be of little use without the Microsoft software for which it was created.[38] As a workaround, numerous tools for (partially) decoding TNEF files exist.[39]

Calendar compatibility
Outlook does not fully support data and syncing specifications for calendaring and contacts, such as iCalendar, CalDAV, SyncML, and vCard 3.0. Outlook 2007 claims to be fully iCalendar compliant; however, it does not support all core objects, such as VTODO or VJOURNAL.[40] Also, Outlook supports vCard 2.1 and does not support multiple contacts in the vCard format as a single file. Outlook has also been criticized for having proprietary "Outlook extensions" to these Internet standards.

Security concerns
As part of its Trustworthy Computing initiative, Microsoft took corrective steps to fix Outlook's reputation in Office Outlook 2003. Among the most publicized security features are that Office Outlook 2003 does not automatically load images in HTML emails or permit opening executable attachments by default, and includes a built-in Junk Mail filter.[41] Service Pack 2 has augmented these features and adds an anti-phishing filter.[42]

Outlook add-ins
Outlook add-ins are small helping programs for the Microsoft Outlook application. The main purpose of the add-ins is to add new functional capabilities into Microsoft Outlook and automate some routine operations. The term also refers to programs where the main function is to work on Outlook files, such as synchronization or backup utilities. Outlook add-ins may be developed in Microsoft Visual Studio or third-party tools such as Add-in Express. Outlook add-ins are not supported in Outlook Web App.

From Outlook 97 on, Exchange Client Extensions are supported in Outlook. Outlook 2000 and later support specific COM components called Outlook AddIns. The exact supported features (such as .NETcomponents) for later generations were extended with each release.

SalesforceIQ Inbox for Outlook
In March 2016, Salesforce announced that its relationship intelligence platform, SalesforceIQ, would be able to seamlessly integrate with Outlook.[43] SalesforceIQ works from inside the Outlook inbox providing data from CRM, email and customer social profiles. It also provides recommendations within the inbox on various aspects like meeting scheduling, contacts, responses etc.

Hotmail Connector
Hotmail Connector setup screen

Microsoft Outlook Hotmail Connector (formerly Microsoft Office Outlook Connector), is a discontinued and defunct free add-in for Microsoft Outlook 2003, 2007 and 2010, intended to integrate Outlook.com (formerly Hotmail) into Microsoft Outlook. It uses DeltaSync, a proprietary Microsoft communications protocol that Hotmail formerly used.[44]

In version 12, access to tasks and notes and online synchronization with MSN Calendar is only available to MSN subscribers of paid premium accounts. Version 12.1, released in December 2008 as an optional upgrade, uses Windows Live Calendar instead of the former MSN Calendar. This meant that calendar features became free for all users, except for tasks synchronization which became unavailable. In April 2008, version 12.1 became a required upgrade to continue using the service as part of a migration from MSN Calendar to Windows Live Calendar.[45]

Microsoft Outlook 2013 and later have intrinsic support for accessing Outlook.com and its calendar over the Exchange ActiveSync (EAS) protocol,[46] while older versions of Microsoft Outlook can read and synchronize Outlook.com emails over the IMAP protocol.[47]

Social Connector
Outlook Social Connector was a free add-in for Microsoft Outlook 2003 and 2007 by Microsoft that allowed integration of social networks such as Facebook, Linkedin and Windows Live Messenger into Microsoft Outlook.[48] It was first introduced in November 18, 2009.[49] Starting with Microsoft Office 2010, Outlook Social Connector is an integral part of Outlook.[50]

CardDAV and CalDAV Connector
Since Microsoft Outlook does not support CalDAV and CardDAV protocol along the way, various third-party software vendors developed Outlook add-ins to enable users synchronizing with CalDAV and CardDAV servers. CalConnect has a list[51] of software that enable users to synchronize their calendars with CalDAV servers/contacts with CardDAV servers.

Importing from other email clients
Traditionally, Outlook supported importing messages from Outlook Express and Lotus Notes. In addition, Microsoft Outlook supports POP3 and IMAP protocols, enabling users to import mails from servers that support these protocols, such as Gmail or Rackspace Email. Microsoft Hotmail Connector add-in (described above) helps importing email from Hotmail accounts. Outlook 2013 later integrated the functionality of this add-in and added the ability to import email (as well as calendar) through Exchange ActiveSync protocol.[46]

There are some ways to get the emails from Thunderbird; the first is to use a tool[52] that can convert a Thunderbird folder to a format that can be imported from Outlook Express. This method must be processed folder by folder. The other method is to use a couple of free tools that keep the original folder structure.[53] If Exchange is available, an easier method is to connect the old mail client (Thunderbird) to Exchange using IMAP, and upload the original mail from the client to the Exchange account.