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My iPhone was stolen two month ago around 16 February 2019. I made sure it was in Lost Mode in iCloud and it was immediately in offline status when I opened iCloud.
I am positive the thief switched it off. Now I am 100% certain the Find my iPhone option was turned on on my iPhone, but will the "Lost Mode" be of any help if it was not turned on on the iPhone? Would it be showing "Offline" if I did not turn on the option?