New Fiat Ducato

I think ad blue is required in fiat comercial engines now

Don’t think so, JV. That’s where Fiat differs from Peugeot.

Thought it was the other way round? as the Pugs are/were fitted with Ford 2.2 engines,which do not need it, whereas Fiat fit their own engines

No, definitely not. 

You edited after I posted, JV. 

Peugeot have been using Euro6 2.0 litre engines requiring AdBlue since the 2017 models. Fiat have been using the 2.2 engines which do not need AdBlue.

The Peugeot 2.0 is smoother and more powerful than the Fiat. We have the 2.0 160 which needs AdBlue. It seems Fiat will be doing similar with their 2020 models.

My van (2016 Pug) has the old Euro 5 2.2 150bhp engine which is non AdBlue. Always sounds like a bag of nails when it starts up although it runs smoothly enough. Don't know whether the newer engines are a bit more sophisticated.

Thats what we had in our  pug powered Autocruise they were made by Ford but used in numerouse 2.2 diesel powered vans and cars ,if it was a 2.2 diesel it was a ford engine

More changes are round the corner for the Peugeot Boxer/Citroen Relay Engine Range.

It seems that the 2017 2 Litre Engine may be about to be replaced by a 2.2 Litre Engine.

"The new Peugeot Boxer is powered by a turbocharged 2.2-litre four-cylinder diesel engine. It's available in three states of tune, with the least potent option producing 118bhp and 300Nm of torque. Mid-range models have 138bhp and 340Nm of torque, while the range topping version has 163bhp and 370Nm of torque.'

The current 130 bhp engine lists 350 of torque so that is a small reduction. I suspect the latest engine change is about emissions 

However although on paper the 2017 engine had more torque (350 versus 320) than the "Bag of Nails" Euro 5 engine  I always felt that the Ford Derived engine actually had more grunt and not as easily drop out of the power band. . 

what i thought was significant was that, yet again, Fiat won't be sharing the new 9- speed alto box with other Sevel brands...PSA Peugeot/Citröen

so, customers using a specific brand of converter using Peugeot base units will still need to order the Fiat chassis if two pedal driving is required...