The documents confirming introduction of tender security on participation in open competition are now the payment order (its copy) or the bank guarantee which conforms to requirements of the Law N 44-FL.
Earlier the participant had to submit the payment order with a mark of bank (its copy certified by bank) or the guarantee included in the register of bank guarantees.
Document: Federal law of 29.12.2015 N 390-FL
I came into force on January 1, 2016