Offline access through IE10;maybe an OWA feature in Exchange 2013?

With all the fuss and bother about the implementation of HTML5 in Internet Explorer 10 (as part of Windows 8), it’s interesting to reflect on how far we have come in terms of web clients for email since Exchange Web Access (subsequently Outlook Web Access) appeared in Exchange 5.0 (1997). The version of Outlook Web App (as OWA is known now) included in the latest version of on-premises Exchange 2010 and in Exchange Online as part of Office 365 is obviously more functional, better performing, and complete than its predecessor.

In fact, OWA has been a huge part of Exchange’s success and a key contributing factor to Microsoft’s ability to launch Office 365 as there’s no way that a cloud service could compete without a great web email client. Of course, the lessons learned in OWA have also been used by Microsoft to build the Exchange Control Panel (ECP) and that’s another major Office 365 component that will probably exert a bigger influence over the on-premises product as new versions of Exchange roll out.

In terms of technology, Microsoft has moved a long way from its implementation of WebDAV and DHTML for OWA in Exchange 2000 as described in Alex Hoffman’s blog or indeed, the EHLO post that covers the same topic in less detail. Compaq was a big partner of Microsoft, possibly the most important partner, for the launches of both Windows 2000 and Exchange 2000, and developed “academy” training events that were delivered to internal and external audiences as part of the process to drum up interest in the new products. I think that Alex came along to a customer Exchange 2000 academy in San Diego to describe how the combination of WebDAV and DHTML had moved OWA from an essentially static web client to a point where the client could have a much more intelligent relationship with the server.

Microsoft has since deprecated WebDAV. Today’s OWA , which uses interfaces such as Ajax and Exchange Web Services, supports the premium version on IE, Chrome, Firefox, and Safari and the basic interface on other browsers. In addition, OWA’s performance in Exchange 2010 is much better than previous versions as Microsoft has done the work to deal with accessing folders that contain tens of thousands of items. All in all, OWA delivers a pretty good work environment that finds few complaints from users.

So what will happen when Windows 8 arrives? The simple answer is “nothing much” because Windows 8 continues to support IE9 on the desktop and you get the same support for OWA through IE9 when you connect to Exchange 2010 or Exchange Online. Things will become more interesting when the Exchange developers have a chance to craft code to take advantage of new features built into IE10. In reading some articles that describe the array of standards-based features supported by IE10, my eye was taken by “IndexedDB”, a W3C initiative with contributions from Google, Mozilla, and Microsoft that is designed to provide browsers with the ability to store offline data. Hmmm… could this be used to give OWA the ability to work offline and deliver a feature that Gmail has offered since September 2011

There's certainly been some rumblings in the press that Microsoft will provide offline access for OWA in Exchange 2013. I guess the really interesting questions are what browsers might support such a feature (for example, will offline mode depend on IndexedDB and what happens for older browsers that know nothing about this W3C initiative) and whether the transition from offline to online mode and vice versa is as smooth as the almost invisible switching of network modes performed by Outlook.

Although I concluded in September 2011 that the provision of offline access for Gmail posed no immediate threat to OWA, I’m pretty sure that offline access is a feature that Microsoft would like to add to OWA. Given that Windows 8 includes a browser that has the necessary support for offline data storage for applications, could we see OWA build on this IE10 feature soon? I guess we’ll just have to wait and see!

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