Hi!
What you mean is that on 20th October 1917 the following Zeppelins went lost : (5 in total!

L44 (shot down-destroyed)
L45 (damaged over North Sea while doing on mine spotting & stranded due to lack of fuel and got destroyed.
L49 (stranded after fuel ran out)
L55 (stranded at Tiefenfort)
L50 drifted as ran out of fuel lost two gondolas into a collission with a hill and with 4 crew into hull drifted over Mediterranean Sea and was never seen again.
What goes on further use for transport?
Maybe beats on the so called Africa ships?
L57 (got destroyed into a collision with his shed at Jūterborg and burned out!

L59 replacing this one was sent with provisions & armory for the German Army to East German Africa....never reached her destination and finally got destroyed on 7th April 1918 probably by lightning near Corsica?
Further the Zeppelins were still used after 1917 for ennemy bombing actions...
L70 was the last one who made an attack on British Isles...destroyed on 5th August 1918! Shot down by Maj. Cadbury & Cpt.Leckie using incendiary ammunition.
VBR
Jempie