The European LG G5 H850 can be officially unlocked through LG’s developer unlock page. Yes, only the European version. Your H850 is from the Middle East? Won’t work. You have an AT&T G5? That’s not an H850, move along.
Warning: This tutorial is only for LG G5 H850 model. The steps written below won’t erase device internal storage, but it’s still recommended to backup your data to device microSD card or PC before starting this tutorial.