If I upgrade to pencil/parallel plugs the old (series) controller will or will not work?

Or it will function but timer will not?

Is the old controller plug compatable with the new style controller?

If I then install a new style controller will it function (correctly) with the new (parallel) plugs?

I have an early type car and it works fine. While the upgrade may have a minor advantage (shorter glow time) it wouldnt be an overall upgrade if I have to push additional glow button or the timer isnt functional.

79 240d