What format should be used for dates and times when using the Pressero API?

All date/time values must be specified according to ISO 8601 standard, like "2018-10-22T15:12:35".
This is noted on the API documentation available here.
Also, when using the Pressero backend, time is localized to the timezone setting of the users. When using the Pressero API, all times  are in UTC timezone values. Times must be read and submitted in UTC timezone values when using the Pressero API.