FMM Tourist Card, Custom Form questions

While preparing for our upcoming visit, I attempted to download an online FMM application, but found it wasn't available/necessary because our first point of entry is Mexico City's Benito Juarez Airport on our way to Zihuatanejo.

Apparently they simply stamp your Passport with the number of days you'll be staying or up to a maximum of 180 days.

What about the Custom Declaration form? Is that necessary to download, fill out and submit upon entry or are they doing away with that form too?

Appreciate hearing of anyone’s experience using Benito Juarez Airport since the new FMM changes have come into effect.

Gracias,
Roberto!