When reading the Zabbix API documentation here, templateScreens is still listed under "rules" even tho it does not seem to be supported anymore as far as I can see.

When executing a API call for configuration.import, and specifying templateScreens the call fails with the following error: 

"data": "Invalid parameter \"/rules\": unexpected parameter \"templateScreens\"."

I have had a look in the source code and templateScreens has also been removed from the 
rules array in ui/conf.import.php in verison 5.2.1. So it seems like documentation issue