I guess they changed the foliage, but really the road network seems the same. Most of my map was still yellow outlined roads.
In the parts where you see grey fragments mixed with yellow, the road remain untouched, but the trees and some of other background was updated. More significant changes like reworked road junctions (and couple of new cities in Denmark and Sweden) look fully grey.
BTW, I just noticed how the developers have changed the requirements for some achievements (it happened in
1.55, actually). Since the map has grown a lot and became more complicated since 2015 (when the first intersections with several separately paintable parts were introduced), now it is virtually impossible to open 100% of the map or buy all the garages within a reasonable amount of time, so today you need to buy some number of garages, or drive some number of kilometres to get the achievement. From the other side, the ones which require to open some number of cities in a new DLC instead of all of them are too easy
.
Also, previously I always made the preferable route length in Gameplay Options smaller when exploring all new DLC maps (and will surely do this for the upcoming Iceland and Ireland
) to get the bigger choice of cargoes for short distance. But, in
Northern Horizons you can easily pick a delivery for 1500-2000 km without leaving the new map, so I have even increased that setup for exploring it.
P.S. Have you heard the new railroad crossing alarm? I don’t know yet did the developers changed all of them, but the one I just heard in Sweden is totally different — instead of tired «ding-ding... ding-ding...» there is faster «bom-bom-bom», and the sound itself is like glass bell
.
.
The fourth photo, they knew exactly what they were doing parking it there beside the freeway. People recognize that stance waiting for speeders! 
