Microsoft today announced it has finally added IMAP support to Outlook.com for all users worldwide. The company has also implemented OAuth, an open standard for authorization used for interacting with protected data, which should open the door for developers looking to build on Outlook.com.

Microsoft continues to insist that Exchange ActiveSync (EAS) is the industry’s best email connectivity option, especially since it is available “on the majority of smartphones and tablets,” including across Windows Phone, iOS, Android, as well as the Windows 8 Mail app and Outlook 2013. Nevertheless, IMAP support means Outlook.com users can finally access their email from software that doesn’t support EAS, including two clients Microsoft specifically underlines for Apple’s OS X: Mail and Thunderbird for Mac.

For those who don’t know, IMAP stands for Internet Message Access Protocol is considered the de facto protocol for email retrieval. It is easily the most requested feature by Microsoft users, going all the way back to the early days of Hotmail.

Microsoft has always pushed back against implementing IMAP, but it recently started to change its mind. Here is how the company explains its new stance:

While we believe that EAS is the most robust protocol for connecting to your email, with syncing in near real time, and superior battery and network efficiency, there are still some devices and apps that haven’t made the upgrade to EAS. As an older protocol, IMAP is widely supported on feature phones and other email clients such as those on a Mac. We heard your feedback loud and clear that this was important.

Furthermore, Microsoft notes IMAP with OAuth gives developers more opportunities to build third-party clients and services that build on Outlook.com. In fact, the company has underlined the first services that integrate with Outlook.com already: TripIt, Sift, Slice, motley*bunch, Unroll.me, and OtherInbox.

Microsoft first broke the news as part of an AMA on Reddit. You can check out the full discussion here.

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