Edit: A quick Google does show there seems to be problems. I think that's a semi significant fail by MS. Does "not supported" equal "doesn't work" though?
In this case, yes, as far as I know, it means "this will not work in any way, and if you try it, Outlook 2013 will stop you and say you're running a stupid-old version of Exchange." I wasn't able to get any farther than installing Outlook 2013 on that computer. The second I tried to get it to load the user's Exchange account, it simply said it was not possible.
I have Office 2010. I don't have Outlook installed. I don't even know what Outlook does. Something to do with e-mail? Every once in a while I get a dialog box telling me I need to configure Outlook and I just cancel out of it and ignore it. I guess Outlook doesn't do anything I need to do...
My guess is that you have a version of Office installed that includes Outlook (which, as Tony said, is pretty much just email and calendaring), and when you click on an email link or otherwise initiate something that would pull up a new email message, it's making a call to Windows to load the default mail program, which will be Outlook unless you've selected something else. If you use webmail for email, you'd need some kind of alternate application running to tell Windows what to do. For example, I have a GMail notification application that handles new email clicks.
And to think at one time we were all on Lotus Notes, ahh the good O'l days.
My wife would laugh hysterically at that. She despised Lotus Notes with every fiber of her being. Perhaps it was the way it was implemented, but among her many complaints about how awful Lotus Notes was, the biggest one was that searching her email always took her at least 10 minutes to get her the results. I'd say the real problem with your company is that they didn't commit. Either go all in with Google Apps (my preference), or go all Exchange. I have no idea why you would move from one solution of Lotus Notes (regardless of how good/bad it is), and go to a two-system solution. Perhaps the biggest IT problem in your company is not the technology but the decision makers
Back on subject, just today in a meeting someone summed MS up pretty good. When talking about Excel issues he made the comment - “Microsoft products aren’t even compatible with themselves.”
Yeah, it sounds like Balmer was a HUGE proponent of keeping that in-fighting. I have no idea how he lasted so long there. MS needs to make some significant changes.
Outlook's the only thing that keeps us tied to Office, there isn't an alternative is there?
Sadly, the only desktop alternative that I know of is no longer being developed:
Thunderbird. Apparently there's a plugin for Thunderbird that will add Exchange functionality. I have no clue how well it works, though.
Tom, you forgot to mention that iOS also has Exchange support built in. I can't remember, does Android have Exchange support?