Could destiny knot pass down 4 IV's?

Question

Or does it only pass down IV's if there are 5 IV's

Answer 1

Since X/Y, Destiny Knot passes down 5 IVs from both parents combined. Both parents combined have a total of 12 IVs, out of which 5 (only one of each stat) are passed down.

PS.- All Pokemon have 6 IVs, no Pokemon comes with a missing IV (even 0 is a valid IV). They may vary though, and could be anything between 0 - 31.

Hope I helped!