The stable version released on October 5th adds a backpack system. The base inventory grid is 8x6, and with the right backpack the capacity can increase to 96 slots.
Small, medium and large backpacks each have six quality levels. Additional cells and overload removal are different mechanics: Pack Mule and armor pockets affect the load. The patch contains loading and item fixes, but the developers also list known bugs. In particular, if there is a problem with using an item from a fire, it is proposed to first transfer it to a backpack.
Sources and checks
V3.3.0 Stable · Steam