The version of the current Intact database is from 2016-09-16.
The version of the current BioGRID database is from 2016-08-25.

The IrefIndex database (version 14, 2015-04-23) was parsed into primary databases and when a multiprotein complex is present, binary interactions between each of its subunits are added to the file. So the number of participants is equal to 2 instead of n (number of proteins of the complex).
 
The files whose name contains "_cutoff" are those whose PPI come from complexes composed of less than n participants.
 
The value of n is indicated after "_cutoff".

In the folder you have files with a cutoff equal to 6, you can use them for complexes like ELP which have 6 subunits; the cutoff 7 is used for the mediator and the cutoff 10 for the bc1.