On a January 29 television interview, Central Bank of Iran (CBI) governor, Valiollah Seif, announced that in the coming fiscal year, March 21st, Iran would no longer use the US dollar in its official financial and foreign exchange reports. 
In a report by the Financial Tribune (the first Iranian-English economic daily), Seif, who is also the head of the Money and Credit council, declared that Iran would convert to a currency that is more suitable for their trade deals.
Iran conducts the majority of its trades with China, the European Union and the United Arab Emirates.  The CBI hinted that Iran would either use the Euro, or a ‘basket of currencies in all official financial and foreign exchange reports.’
The move to switch to another currency has been in the works since 2016, but some speculate that Trump’s ban on seven Muslim-majority countries for at least 90 days (Iran, Iraq, Libya, Somalia, Sudan, Syria, and Yemen) sped up this process. 
In response to Trump’s ban, Iran has announced that it will stop issuing Visas to US citizens. 
In a hidden retaliation, Congress passed a bill that authorized the US Armed Forces to prevent Iran from obtaining nuclear weapons.  Thereby, justifying the use of force and invasion into Iran so long as Congress assumes Iran is stockpiling nuclear weapons. This is an eerily similar statement to when George W. Bush invaded Iraq looking for ‘weapons of mass destruction.’
A look back into history will reveal that anytime a country’s leader has attempted to shift away from the US dollar, their countries have been invaded and ransacked. From Muammar Gaddafi’s Libya, to Syria’s Bashar al-Assad to Saddam Hussein of Iraq, all these countries have been demolished and outright bombed since their stray from the United States’ currency.
Only time will tell if this match-up between Iran and the US will be any different.