First In First Out - FIFO - means the oldest stock will be allocated to orders first (i.e. batches with the lowest priority sequence will be allocated and subsequently dispatched first). We can explicitly configure our WMS to operate as FIFO by setting it in the:

• Linnworks application > General Settings > Warehouse Management
• Select the WMS location which you want to configure
• Check First In, First Out

This setting will enforce a rolling priority sequence when stock is booked in. 

Worth noting the following: 

• Stock booked in from the PO in the same binrack will retain the same priority sequence.
• Stock booked in directly (without PO) to the same binrack in the same day will retain the same priority sequence. 
• Stock moved from one binrack to another will combine only if the batch number in the destination binrack is the same, the priority sequence of the destination binrack will be retained. 
• Priority Sequence can be changed by user by editing inventory.
• Priority Sequence is essentially a sorting mechanism therefore priority sequence number is not unique for a batch, they can be the same, negative or very large (max 2147483647, in case you want to push a batch all the way to the end, or -2147483647 if you want to bring it forward) 
• Macro can be used to create a bespoke and a very custom allocation mechanics. 

See Also:

• Priority Sequence Stock Allocation - Pickwaves
• How to Use FIFO to Manage Aged Stock