Recently, the creators of The Sims 4 introduced an updated family tree for the life simulator, allowing players to "tell more intricate stories about sim families":
Sims now have names for relationships with relatives by marriage, stepbrothers and stepsisters, great-grandmothers and great-grandfathers, and more! Distant relatives are now also displayed in the family tree
For example, The Sims 4 now includes relationship names such as: mother-in-law, father-in-law, sister-in-law, brother-in-law, daughter-in-law, son-in-law, distant relative, distant relative by marriage, stepsister, stepbrother, stepmother, and many others.
The update did not go smoothly: shortly after release, another patch was issued that was supposed to roll back the version. The game returned to the previous 1.120, but some users now cannot launch The Sims 4 — clearing the game folder in "Documents" helps)