401k and bitcoin

Please correct me if I'm wrong, but Did I hear correctly that recently Trump said he would allow us to use our 401ks to buy BTC? how would that work? I currently have one at one of the big guys. Also would it only be going froward from your paycheck or could you use existing 401k values to buy? I have one of the normal 401ks that's set for a future date. It would be kind of amazing if this was allowed. Also would it be spot BTC or would it need to be an elf or btc treasury company? Would appreciate your thoughts on this thanks..