Question: what is the most current ios for iphone
[{'answer': 'iOS 11.4'}, {'provenance': [{'wikipedia_id': '18195583', 'title': 'IOS version history', 'start_paragraph_id': 1, 'start_character': 0, 'end_paragraph_id': 1, 'end_character': 688, 'bleu_score': 0.867663037082484, 'meta': {'yes_no_answer': 'NONE', 'annotation_id': 16840360803370986776}, 'section': 'Section::::Abstract.'}]}]