According to my own test, multiple email addresses in "To" field are allowed, but only if the addresses are entered one at a time. Method 1: Tap "To" field > enter one address > enter character "," (comma) > enter another address > enter character "," (comma). Method 2: Tap "To" field > enter one address > press "enter" key > tap "To" field again > enter another address > press "enter" key. The following method is not allowed: Copy a string of multiple addresses separated by commas > tap "To" field > paste that string.