I have been trying to get activesync to work with Outlook.com and have found a number of problems. I have submitted bug reports for each (76515-76518)), in order to not forget about them, but three of the four probably require some discussion on the list. 1) Outlook.com requires protocol version 14.0. It does not support any earlier or later protocols. We currently support version 12.1 (which seems to be supported by most Exchange servers, even those which also support 14.0 or 14.1). The code includes a conditional to select whether we claim to support 12.1 or 14.0. But it looks like that only really changes what we claim -- the only case the version seems to be checked is when sending mail (which we don't use in SyncEvolution). A quick test seems to show that claiming to be 14.0 allows syncs to work with outlook.com -- but I have not yet reviewed the differences to see if I can find things which break. Assuming that we either don't need to change the operation, or can easily change it, there is a bigger question of whether to switch to claiming 14.0. At the moment, there is no attempt to negotiate protocol version: if we switch to 14.0, servers which only support 12.1 will stop working. Negotiation would involve some complexity (adding a new message exchange or re-trying connections with each protocol version) -- is it worth it? Are there any servers still running which do not support 14.0? 2) Outlook.com does not like NTLM auth. Activesyncd explicitly tells libsoup to enable NTLM, which causes outlook.com to return an error. Disabling NTLM allows outlook.com to work, and also works with my work server (it always requires Basic auth anyway, even when we start by sending NTLM). Apparently autodiscover (which we don't support) is supposed to tell you whether to use NTLM or Basic. But surely we can't provide valid domain credentials using NTLM anyway, can we? Is there any reason to specify NTLM? 3) Outlook.com does redirects, to redirect access to a specific server based on the username. Should we bother to go to the extra effort to implement these redirects? Does any other service use them? It is not clear that the user can find out which server to specify if we don't implement the redirect.