I realize OS10 is old and support is non-existent, and as calendars upgrade it will leave my Q10 in the dust as far as calendars go. But, I am hoping there is a remote workaround to get my blackberry Q10 calendar to sync with Zoho.
Through settings, I used the Caldav sync for Zoho Calendar and set the server address to https://calendar.zoho.com as instructed by the zoho site. When I go to add an appointment in my Q10, I can choose my zoho calendar when I add an appointment. However, it does not show on the zoho calendar on my desktop.
As an experiment, I added a second calendar with a different name from the desktop computer on the zoho website. I then went to my Q10 and saw that I could choose either one of the two calendars I set from the zoho website. This is proof that Zoho is talking with my Q10, but is it not synching appointments. For now, I am assuming this is a lost cause, unless some one knows a work around.