MOU is an extension of current ceasefire for at least 60 days while they go into technical talks about longer-term issues including nuclear program and financing of terrorism. It includes opening of the Strait and commitment by Iran to refrain from attacking shipping.
If vessels start going through and are struck by drones, missiles, attack boats or mines, it would derail the entire deal. Stakes are high for Iranians to meet commitments. In Lebanon, Iran must compel Hezbollah to refrain from attacking northern Israel.