Oxygen Not Included [Steam] is such an addictive game it's quite crazy and the Occupational Upgrade seems to be pretty good.
This update even came with an animated short to enjoy:
Klei could probably turn that into a series, beautiful animation as always from them.
It comes with a refreshed job progression system for your Duplicants. They will now be able to wear many hats, literally, they now wear hats to show off what job they've currently been given.
Duplicants will be able to rise through the ranks in specific jobs, with jobs now giving them an attribute boost in the related field of work. Some jobs even give special perks, so rising through the ranks can unlock special skills for them.
There's also new stuff to build, like the Farm Station which will enable you to create a Greenhouse. Duplicants assigned there can make a special fertiliser and distribute it to nearby crops. A new Power Control Station will now create a Power Plant, so Engineering Duplicants will be able to make upgrade materials, allowing them to tinker with nearby generators to increase their power. Duplicants also need a bit of fun, so there's now a Recreation Room too.
They've also expanded the Automation system! Adding in Conveyor Rails, Loader and Receptacle to allow you to transport goods around easily. There's also a New Conveyor Overlay to get a good idea of what's going where as well. An Auto-Sweeper to suck up ore and debris in its range and fire it into containers—nice! There's more as well, lots of new goodies to play with.