Recently was asked for supported configurations for server side sync for CRM 2015 online. Here is the matrix:
|
CRM deployment |
Email system |
Email synchronization |
Appointments, contacts, and tasks synchronization |
Protocol |
|
CRM (on-premises) |
|
Yes |
Yes |
Exchange Web Services |
|
CRM (on-premises) |
|
Yes |
No |
POP3/SMTP |
|
Microsoft Dynamics CRM Online |
Exchange Online |
Yes |
Yes |
Exchange Web Services |
|
Microsoft Dynamics CRM Online |
|
Yes |
No |
POP3/SMTP |
Source: Technet
Hope it helps!
MSDYNAMICSBLOG BY DEEPESH 
Reblogged this on mfonsell and commented:
Dynamics CRM 2013/2015 and supported Server Side Sync scenarios