Exactly what it says on the subject, a save created on 0.17.x no longer loads without crashing, and the log gives a similar error:
Extra information: this was a multiplayer game, none of the players who played in it can load the save in 0.17.3, and everyone saved at different points, attaching the save-file if it helps:Error Controller.cpp:393: mainInventory->getHandPosition() == NO_ITEM_STACK_INDEX was not true