If you have the Full Traceability Add-on, you'll notice that Item cards included the option to switch on/off serial number tracking at the item level (per product).
Note: Serial number tracking can only be enabled for finished products
Since serial number tracking can be set at the item level, this also affects all variants of the item. Enabling/disabling serial number tracking for an item will only affect that item.
Manually enabling product serial number tracking
Navigate to the Items screen and select a product from the list.
Enable Serial numbers.
NOTE: Serial number tracking in Katana is available with the Full Traceability add-on
If you're manufacturing serial number traced products, you can automatically generate serial numbers based on a specified format.
{ORDER_NO} shows the MO identifier
{SEQ_START} begins a sequence of numbers
You can add any combination of numbers and letters
Uncheck Automatically generates MO serial numbers to turn off the automatic generation of serial numbers.
Serial tracking has been enabled for all variants of the item.