I do not “use” the writings of early church fathers, in the sense that I use the inspired biblical books.  I read them, and I study them, but I do not use them (unlike the Roman Catholic and Orthodox churches which literally “use” church father writings to establish authoritative church teaching).  So, the question is not which version I use, but instead it is which is more likely to be the original by Ignatius.

My understanding is that according to the consensus of scholars, Ignatius only wrote the shorter version, and that the longer version is an interpolation, added by later writers.   I do not know of a significant theological difference between the content in the shorter/authentic letter, so I am not sure that it raises a significant issue for students of church history, but I would study more closely the shorter version, as it is a snapshot of church teaching by an influential bishop at the very beginning of the second century.

John Oakes