FFG reset the timeline more or less back to 1st edition, around 1123 I believe.
Everything before that you can safely assume is the same as in 4e.
There are some minor changes to the setting but the broad strokes are the same; Doji Hoturi being replaced with Doji Hotaru, the dragon clan being given the role of recording the history of the empire, the phoenix got a new family, etc.
The RPG has hints of the new plotlines but aside from a few novels the only real changes to the lore are published with the LCG.
As I understand it the entire plotline of 5e has taken place in less than a year. The unicorn have upset the lion by canceling a big wedding, the phoenix forced the unicorn to reveal the secrets of their meishodo magic to the imperial family to prove it isn't causing some elemental imbalance that they are worried about. the Dragon are dealing with a decline in birth rates and a heretical cult. Somewhere in all of this I think the emperor died and his heir went missing? I think the Scorpion clan champion is on the throne as a regent while they find the kid... I've heard that there might be a Scorpion Clan Coup going on but it's not the same as the one you'll be thinking of.