Great news reported by several outlets, also verified in the Xbox One store itself.... Unlike Forza Horizon 3, the Ultimate edition of Forza Horizon 4 will include 2 expansion packs to be released later in December 2018 and the 'First half of 2019".
FH3's ultimate edition only included the Car pass and other miscellaneous items, but it did not give you access to Blizzard Mountain or the Hot Wheels expansions. I remember some people did not appreciate that because you would think that getting the "Ultimate Edition" would give you access to the expansion packs as well.
Personally I did not mind simply because the base FH3 game was well worth it for me, but it definitely makes more sense the way they are doing it now with FH4, I just want the quality to remain the same, I don't want to see a drop just because they are offering a better deal now. It's also nice to see the store description for both, it states :
"This add-on will introduce a new world location, vehicles, gameplay"
Maybe one of the expansions could be in Japan, would be cool considering the rumors we had about FH4. Anyways, this is fantastic news and I cannot wait to get my hands on this game.