OPEN_ INVENTORY
When this option is not enabled, the inventory will be opened silently depending on the Minecraft version chosen using ViaFabricPlus.
If the protocol contains com.viaversion.viabackwards.protocol.v1_12to1_11_1.Protocol1_12To1_11_1 and the client status packet is supported, the inventory will be opened silently using openInventorySilently. Otherwise, the inventory will not have any open tracking and the server will only know when clicking in the inventory.
Closing will still be required to be done for any version. Sad. :(