Updated October 2026: This post has been expanded from its original December 2013 version from a brief product announcement into a historical explainer on how email, calendar and contact syncing with Outlook actually worked in 2013, and how it works now. It is a historical account; details describe the time it covers, not today.
At the end of 2013, this site, then run by an email hosting provider, posted a short note announcing the beta of a feature called Outlook Sync: a way to keep calendar and contact data in step between its webmail service and Microsoft Outlook 2013. The announcement itself was brief, and we are not going to reconstruct product details that were specific to that provider's beta. What is worth preserving is the bigger picture it sat inside.
In 2013, "sync your email with Outlook" was a surprisingly tangled subject. Several competing technologies did the job in different ways, each with its own strengths and limits, and the landscape was shifting underneath users that very year. This post explains, as history, how Outlook syncing worked around 2013, why so many providers were announcing sync features at the same time, and how the same problem is solved today.
What "syncing with Outlook" actually means
It helps to separate three kinds of data that a mail account can hold: messages, calendar events and contacts. Plain email access has long been easy. The harder part was keeping calendars and contacts consistent across a web interface, a desktop copy of Outlook and a phone, so that an appointment added on one showed up on the others. In 2013, a few different protocols competed to do this.
| Technology | What it syncs | Notes in 2013 |
|---|---|---|
| POP3 | Email only (usually downloads and removes) | Oldest method; no calendar or contact sync |
| IMAP | Email only, kept in sync across devices | Widely supported; no native calendar or contacts |
| Exchange ActiveSync (EAS) | Email, calendar, contacts (and tasks) | Microsoft protocol; push sync; licensed by many providers |
| CalDAV / CardDAV | Calendar (CalDAV) and contacts (CardDAV) | Open standards; not supported natively by desktop Outlook |
Sources: Microsoft and Google documentation; Wikipedia entries for Exchange ActiveSync, CalDAV and CardDAV. "Native" means built in without an add-on.
Exchange ActiveSync: the push option
Exchange ActiveSync, usually shortened to EAS, is a Microsoft protocol that first appeared in the early 2000s as part of Microsoft's mobile server software. Its appeal was that it handled email, calendar and contacts together, with "push" delivery so changes appeared quickly, and over the years it added tasks and notes. Microsoft licensed EAS widely, which is why it became the common language for syncing phones with many different mail systems, not just Microsoft's own.
For desktop Outlook, EAS became directly relevant in 2012 and 2013. Outlook 2013 could connect to Microsoft's consumer mail, Hotmail and the new Outlook.com, using Exchange ActiveSync, which meant the old "Outlook Hotmail Connector" add-in was no longer required. A preview write-up in July 2012 noted that this new connection even brought tasks into Outlook, which the older connector had not synced. For many home users, that was the first time their webmail calendar and contacts flowed into desktop Outlook without extra software.
CalDAV and CardDAV: the open alternative
The open-standards camp used two related protocols. CalDAV, finalized as an internet standard in 2007, handles calendar data; CardDAV, finalized in 2011, handles contacts. Both build on WebDAV, an extension of the web's own HTTP protocol, and they were widely adopted by open-source servers and by Apple.
The snag for Outlook users was that desktop Outlook never supported CalDAV or CardDAV natively. Bridging that gap required a third-party add-in. The best-known is the open-source Outlook CalDav Synchronizer, which began in 2015 as a university project in Vienna and provides two-way sync between Outlook and any CalDAV or CardDAV server, including services such as Google, Nextcloud and iCloud. A provider whose calendar spoke CalDAV could therefore tell its users to install that plugin and point it at the provider's calendar address, rather than build sync into Outlook itself.
Why so many sync announcements landed at once
Providers were not announcing Outlook sync features in late 2013 by coincidence. Two upstream changes pushed everyone in the same direction.
First, Google pulled back on EAS. In a December 2012 "winter cleaning" post, Google said that from January 30, 2013, free consumer accounts could no longer set up new devices using Google Sync, its EAS implementation. Google pointed users instead to the open protocols: IMAP for mail, CalDAV for calendars and the newly launched CardDAV for contacts. Paying Google Apps customers kept EAS. Microsoft, needing to keep Windows Phone working with Google accounts, got an extension to July 31, 2013 and said it would lean on CalDAV, CardDAV and IMAP afterward.
Second, Microsoft was moving. Outlook.com had launched to the public in February 2013, and in September 2013 Microsoft added IMAP support, along with OAuth sign-in, specifically to make Outlook.com easier to use from Mac mail clients and other apps that had not adopted EAS. For independent email hosts, all of this meant customers increasingly expected their mail, calendar and contacts to sync cleanly into Outlook, and the providers that could offer it advertised it. A provider's "Outlook Sync" beta in December 2013 fits squarely into that moment.
- June 2009
Google Apps Sync for Microsoft Outlook launches for business and education accounts. - July 2012
Outlook 2013 preview connects to Hotmail via Exchange ActiveSync, dropping the old connector. - December 14, 2012
Google discontinues Google Calendar Sync for Outlook. - January 30, 2013
Google ends new EAS device setups for free consumer accounts; points to CalDAV/CardDAV/IMAP. - February 2013
Outlook.com launches publicly. - September 2013
Outlook.com adds IMAP and OAuth support. - December 2013
Email hosts, including this site's former operator, promote Outlook calendar and contact sync.
The trade-offs users faced
Each approach involved a compromise, and this is the part that still rings true. If you only used IMAP or POP, your mail synced but your calendar and contacts did not, so people often ran mail through IMAP and calendars through a separate CalDAV setup. EAS kept all three together and pushed changes quickly, but it was Microsoft's protocol and not every provider licensed it, and even where it worked it had rough edges, such as limits on sending from an alias or syncing the drafts folder. CalDAV and CardDAV were open and flexible but needed an add-in to work with desktop Outlook at all. There was no single clean answer in 2013, which is precisely why "we now sync with Outlook" was worth announcing.
What happened next
The picture kept shifting after 2013, mostly toward consolidation. Microsoft finished migrating Outlook.com onto its Office 365 Exchange infrastructure, and in February 2017 it turned off Exchange ActiveSync for the desktop Outlook client, telling users to re-add their Outlook.com accounts as full Exchange accounts, which fixed many of EAS's old limitations around aliases, drafts and contact groups. EAS lived on mainly as the way phones and tablets sync, which is still largely true.
On the Microsoft side, the old built-in Windows Mail and Calendar apps reached end of support on December 31, 2024, replaced by a new Outlook for Windows that natively connects to Gmail, Yahoo, iCloud and other IMAP accounts and pulls in their calendars and contacts. In October 2025, Microsoft added improved iCloud mail, calendar and contact support across the new Outlook for Windows, Outlook for Mac and the mobile apps, using modern OAuth sign-in instead of app-specific passwords. The classic desktop Outlook still leans on older methods for some of this.
How to sync email, calendar and contacts with Outlook today
The technologies have settled, so the practical advice is simpler than it was in 2013:
- Add the account natively first. In current Outlook, adding a Microsoft, Gmail, Yahoo or iCloud account usually brings mail, calendar and contacts automatically, with no add-in. Try this before anything else.
- Know what each protocol carries. IMAP and POP move only email. For calendar and contacts you need Exchange/EAS or CalDAV and CardDAV. If a calendar is not appearing, that mismatch is the usual reason.
- Use a CalDAV/CardDAV add-in for other providers. If your host uses open standards and you are on classic desktop Outlook, a maintained plugin such as Outlook CalDav Synchronizer bridges the gap.
- Prefer modern sign-in. Where a provider offers OAuth, use it instead of app-specific passwords; it is both easier and more secure.
- Check which Outlook you are running. The new Outlook for Windows and classic Outlook differ in what they support, so instructions that work in one may not match the other.
The bottom line
The 2013 announcement that prompted this post was one small entry in a busy year for email syncing. Behind it sat a genuine problem, keeping mail, calendars and contacts consistent across webmail, desktop Outlook and phones, and several rival technologies racing to solve it as Google stepped back from Exchange ActiveSync and Microsoft pushed Outlook.com forward. The specific beta is long gone, but the underlying ideas, EAS for all-in-one push sync, CalDAV and CardDAV as open standards, and IMAP for mail, are still the pieces that make an inbox show up correctly in Outlook today.
Sources
- Google Workspace Updates: Google Apps Sync for Microsoft Outlook (June 2009)
- Pocketables: Outlook 2013 connects to Hotmail via Exchange ActiveSync (July 2012)
- Google: Winter cleaning (Dec. 2012)
- Redmond Magazine: Google ActiveSync support changes (Jan. 2013)
- InformationWeek: Microsoft: Outlook making progress vs. Gmail (Feb. 2013)
- TechCrunch: Microsoft adds IMAP support to Outlook.com (Sept. 2013)
- Wikipedia: Exchange ActiveSync
- Wikipedia: CalDAV
- Wikipedia: CardDAV
- Outlook CalDav Synchronizer (GitHub)
- Microsoft Support: Windows Mail, Calendar and People are becoming Outlook
- Yahoo Tech: Outlook gets better iCloud support (Oct. 2025)
Top image: "Lenovo G500s laptop-2905" by Raimond Spekking, CC BY-SA 4.0, via Wikimedia Commons (resized). Charts by Thank You Robot.
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