Federation Dropped Third Strike Rule

[Tsmokie]

1st base is occupied with less than 2 outs and the catcher drops the 3rd strike. The batter runs down towards first base and the runner on 1st runs towards second. The batter draws a throw to first base. In Federation is this considered interference? I remember the rule being changed a couple of years ago that it was not considered interference, but I can't find it in the book. Any help would be appreciated.

Thanks