ModifiedTime missing from Zoho Desk Rest API ticket response

ModifiedTime missing from Zoho Desk Rest API ticket response

I am attempting to create an integration to Zoho Desk via the API to make ticket information available in our system.  I am using the Zoho Desk Rest API documented here:  https://desk.zoho.com/DeskAPIDocument#Introduction.  In the section describing the Ticket JSON response it states that there is a field called modifiedTime.  When using the API this field does not come back.  I've taken a look at other community topics and they mentioned use of a parameter called "selectfields".  This selectfields parameter does not seem to work now, though I think they are utilizing an older API so this probably does not apply.

Is there a reason why ModifiedTime is not returned and if it can be returned why can it not be used to sort a set of tickets when using the List All Tickets API?

Thanks,
Jed