Microsoft Outlook is a personal information manager software system from Microsoft, available as a part of the Microsoft 365 software suite. Primarily popular as an email client for businesses, Outlook also includes functions such as calendaring, task managing, contact managing, note-taking, journal logging, web browsing, and RSS news aggregation.
Individuals can use Outlook as a stand-alone application; organizations can deploy it as multi-user software (through Microsoft Exchange Server or SharePoint) for shared functions such as mailboxes, calendars, folders, data aggregation (i.e., SharePoint lists), and as appointment scheduling apps.
Versions Outlook replaced Microsoft's previous scheduling and email clients, Schedule+ and Exchange Client.
Outlook 98 and Outlook 2000 offer two configurations: Internet Mail Only (aka IMO mode): A lighter application mode with specific emphasis on POP3 and IMAP accounts, including a lightweight fax application. Corporate Work group (aka CW mode): A full MAPI client with specific emphasis on Microsoft Exchange accounts.
Perpetual versions of Microsoft Outlook include:
Name Version numberThe version numbers follows the Office numbers. Release date Notes Outlook 97 8.0 January 16, 1997 Included in Office 97 and bundled with Exchange Server 5.0 and 5.5. This was a renamed and slightly upgraded version of the Microsoft Exchange client. Outlook 98 8.5 June 21, 1998 Freely distributed with books and magazines to cope with the newest Internet standards such as HTML email. Outlook 98 setup was based on Active Setup which also installed Internet Explorer 4. Outlook 2000 9.0 June 27, 1999 Included in Office 2000 and bundled with Exchange 2000 Server Outlook 2002 10 May 31, 2001 Included in Office XP Outlook 2003 11 November 20, 2003 Included in Office 2003 (incl. Standard Edition for Students and Teachers) and bundled with Exchange Server 2003 Outlook 2007 12 January 27, 2007 Included in Office 2007, except Office Home and Student edition Outlook 2010 14 July 15, 2010 Included in Office 2010 Home and Business, Standard, Professional and Professional Plus Outlook 2011 for Mac 14 October 26, 2010 Included in Office for Mac 2011 Home and Business Outlook 2013 15 January 29, 2013 Included in Office 2013, except Home & Student edition Outlook for Mac 15.3 October 31, 2014 Included in Office 365, except some commercial editions Outlook 2016 16 September 22, 2015 Included in Office 2016 and Office 365 Outlook 2016 for Mac 15.12 September 25, 2015 Included in Office 2016 and Office 365 Outlook 2019 16 September 24, 2018 Included in Office 2019 and Office 365 Outlook 2019 for Mac 16.17 September 24, 2018 Included in Office 2019 and Office 365 Outlook for Phones & Tablets 1.3 2015 Included in Office 365, except some commercial editions Includes iOS and Android support
Microsoft Outlook
Microsoft Outlook is an email and personal information manager software primarily used in professional settings. As part of the Microsoft Office suite, it offers email management, contact storage, calendar scheduling, and task tracking. Outlook can function independently or as part of a larger Microsoft ecosystem, including integration with SharePoint for file sharing. While it stores email data locally for offline access, newer versions restrict link opening to Microsoft's own browsers.
Privacy is severely degraded in the latest versions, as the new Outlook sends passwords, mails and other data to Microsoft.
Macintosh
Before 2011, Microsoft did not offer Outlook for Mac. Instead, it provided Microsoft Entourage (and earlier, Outlook Express for Mac). Microsoft Entourage was Microsoft's personal information manager for Mac, including email, calendar, contacts, and tasks, and Outlook for Mac was included with Office for Mac 2011 Home & Business.
Microsoft Entourage was Microsoft's email app for Mac. It was similar to Outlook but initially lacked full native support for Microsoft Exchange. Later versions, especially Entourage 2008 Web Services Edition, added much better Exchange support, but Entourage remained a separate application from Outlook.
Entourage was replaced by Outlook for Mac 2011, which offered improved compatibility with Microsoft Exchange and a user interface more consistent with Outlook for Windows, although feature parity was still incomplete. It is the first native version of Outlook for Mac OS X.
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. 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). The "New Outlook for Mac" client, included with version 16.42 and above, became available for "Early Insider" testers in the fall of 2019, with a public "Insider" debut in October 2020. It requires macOS 10.14 or greater and introduces a redesigned interface with significantly changed internals, including native search within the client that no longer depends on macOS Spotlight. Some Outlook features are still missing from the New Outlook client as it continues in development.
To date, the Macintosh client has never had the capability of syncing Contact Groups/Personal Distribution Lists from Exchange, Microsoft 365 or Outlook.com accounts, something that the Windows and web clients have always supported. A UserVoice post created in December 2019 suggesting that the missing functionality be added has shown a "Planned" tag since October 2020.
In March 2023, Microsoft announced that Outlook for Mac will be available for free. This means that users no longer need a Microsoft 365 subscription or an Office licence to use the program.
Phones and tablets First released in April 2014 by the venture capital-backed startup Acompli, the company was acquired by Microsoft in December 2014. On January 29, 2015, Acompli was re-branded as Outlook Mobile—sharing its name with the Microsoft Outlook desktop personal information manager and Outlook.com email service. In January 2015, Microsoft released Outlook for phones and for tablets (v1.3 build) with Office 365.Compare: This was the first Outlook for these platforms with email, calendar, and contacts.
On February 4, 2015, Microsoft acquired Sunrise Calendar; on September 13, 2016, Sunrise ceased to operate, and an update was released to Outlook Mobile that contained enhancements to its calendar functions.
Similar to its desktop counterpart, Outlook mobile offers an aggregation of attachments and files stored on cloud storage platforms; a "focused inbox" highlights messages from frequent contacts, and calendar events, files, and locations can be embedded in messages without switching apps. The app supports a number of email platforms and services, including Outlook.com, Microsoft Exchange and Google Workspace (formerly G Suite) among others.
Outlook mobile is designed to consolidate functionality that would normally be found in separate apps on mobile devices, similar to personal information managers on personal computers. It is designed around four "hubs" for different tasks: "Mail", "Calendar," "Files" and "People". The "People" hub lists frequently and recently used contacts and aggregates recent communications with them, and the "Files" hub aggregates recent attachments from messages, and can also integrate with other online storage services such as Dropbox, Google Drive, and OneDrive. To facilitate indexing of content for search and other features, emails and other information are stored on external servers.
Outlook mobile supports a large number of different e-mail services and platforms, including Exchange, iCloud, Gmail, Google Workspace (formerly G Suite), Outlook.com, and Yahoo! Mail. The app supports multiple email accounts at once.
Emails are divided into two inboxes: the "Focused" inbox displays messages of high importance, and those from frequent contacts. All other messages are displayed within an "Other" section. Files, locations, and calendar events can be embedded into email messages. Swiping gestures can be used for deleting messages.
Like the desktop Outlook, Outlook mobile allows users to see appointment details, respond to Exchange meeting invites, and schedule meetings. It also incorporates the three-day view and "Interesting Calendars" features from Sunrise.
Microsoft announced in 2026 that the previous Outlook Lite app would be discontinued, with Outlook Mobile serving as its successor.
Files in the Files tab are not stored offline; they require Internet access to view.
Security
Outlook mobile temporarily stores and indexes user data (including email, attachments, calendar information, and contacts), along with login credentials, in a "secure" form on Microsoft Azure servers located in the United States. On Exchange accounts, these servers identify as a single Exchange ActiveSync user in order to fetch e-mail. Additionally, the app does not support mobile device management, nor allows administrators to control how third-party cloud storage services are used with the app to interact with their users. Concerns surrounding these security issues have prompted some firms, including the European Parliament, to block the app on their Exchange servers. Microsoft maintains a separate, pre-existing Outlook Web Access app for Android and iOS.
Outlook Groups Outlook Groups was a mobile application for Windows Phone, Windows 10 Mobile, Android and iOS that could be used with an Office 365 domain Microsoft Account, e.g. a work or school account. It is designed to take existing email threads and turn them into a group-style conversation. The app lets users create groups, mention their contacts, share Office documents via OneDrive and work on them together, and participate in an email conversation. The app also allows the finding and joining of other Outlook Groups. It was tested internally at Microsoft and launched September 18, 2015, for Windows Phone 8.1 and Windows 10 Mobile users.
After its initial launch on Microsoft's own platforms the application was released for Android and iOS on September 23, 2015.
Outlook Groups was updated on September 30, 2015 to introduce a deep linking feature as well as fix a bug that blocked the "send" button from working. In March 2016 Microsoft added the ability to attach multiple images and the most recently used document to group messages, as well as the option to delete conversations within the application program.
Outlook Groups was retired by Microsoft on May 1, 2018. The functionality was replaced by adding the "Groups node" to the folder list within the Outlook mobile app.
Internet standards compliance
HTML rendering Outlook 2007 was the first Outlook to switch from the Internet Explorer rendering engine to Microsoft Word 2007's. This meant that HTML and Cascading Style Sheets (CSS) items not handled by Word were no longer supported. On the other hand, HTML messages composed in Word look as they appeared to the author. 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 an Outlook email.
Support of CSS properties and HTML attributes