Since we have started tesing Zimbra our Mobile Users complain about the fact that New-Line characters enterd on the mobile (or the webinterface) are not being handled correctly by the Zimbra Mobile Syncer (Nokia MailForExchange work correctly).
With 4.5.1 the situation got worse, new-lines are still not handled. Now Appointment Descriptions/Notes entered on the mobile do not show up at all in the appointment edit view of the web interface. (They do show up in the little bubble popup that shows when moving the cursor over the appointment in the webif, so this is probably a webif issue at some level).
I have created a bug report for this problem, but it has remained unfonfirmed for the last 1.5 months ...