I am afraid that there is nothing official yet.
My expectation is that by the latest tomorrow (in line with the documentation) the ICSDs will receive notice of a determination by the Calculation Agent of a Settlement Disruption Event. If that is the case, the bond will most likely pay the coupon in US Dollars on the Postponed Fixed Interest Date, which I believe will be 8th August (being 10 London, Moscow and New York Business Days after the Fixed Interest Payment Date.)
The documentation allows for the bond to be paid in Russian Rouble still if the Calculation Agent subsequently determines that a Settlement Disruption Event is no longer occurring in sufficient time for all notices to be sent and the payment to subsequently be made before the 8th August, but this would only be likely if it were to be remedied by the 2nd or 3rd August, and that is not what I am currently expecting to be the case.
I hope that helps.