The Russians are going to be going into panic mode again. They will be lining up at banks to turn in their old $100 bills to get the new ones. They think the old ones won't be honored after the new ones are released.
That happened in 1997 when the current $100 bill with the water mark came out replacing the previous bill. At that time there were more $100 bills in circulation in Russia than in the U.S. because the average Russian didn't carry credit cards then and no Russian would trust another Russian for getting paid with a check, so cash was king.
I was working in Moscow then and the U.S. Treasury Department had to get signs made to put in all the banks and currency exchange kiosks explaining the old bills would be honored forever.
But the Russians didn't trust us because when the Soviet Union dissolved and Russia started issuing its own roubles to replace the Soviet roubles, the Russian government gave everyone just 3 days to turn in their old money and get the new bills.
After those three days, the previous roubles became worthless except as souvenirs, which I have a supply of.