Outlook 2007 is architecturally closest to Outlook 2003, and therefore is the most unreliable in terms of connection/syncing quality. It’s still a supported configuration but your experience will be noticeably improved if you have a large mailbox, or syncing problems once you move to 2010 or 2013.
Outlook 2010 and 2013 are architecturally similar, but Outlook 2013 will always get patched before 2010. It just makes sense that Microsoft will patch the latest and greatest version of Outlook first, and then subsequently backport those fixes to previous versions. Outlook 2010 will usually get all the same patches as 2013 (where applicable), but backporting all the way to 2007 is a much riskier gamble and not always the route that Microsoft chooses to pursue.
So if you have the ability to deploy Outlook 2013 I would recommend that as a first choice, since it will have the most reliable, secure, and up to date connection information for Office 365. The next best bet is 2010, and if you are forced to use Outlook 2007 because of a business or technical constraint know that it is possible but not the best user experience you could have with Office 365.
- What version of Outlook 2007, 2010, or 2013 is supported on Office 365?
The general rule with Office is that you must have the latest service pack installed, and then where possible all of the latest updates. There are many version checks on incoming connections to Office 365 that will cause Outlook to behave differently if you don’t have the latest patches installed, so I recommend always installing Office updates (especially Outlook) unless you have personally experienced issues testing a patch.
It’s extremely important to test patches first since Microsoft isn’t able to test every configuration their customers run Outlook/Office 365 in. That way in case your particular configuration isn’t compatible with the patch you’ll know ahead of time before it affects your Outlook users. This happens rarely, but if it does you’ll be in a much better position to protect your user base.
If you still have issues with Outlook and Office 365 after installing the latest patches there are a few places you can look for assistance:
