All Release NotesCustom line items behavior improved6 October 2017Composable CommerceHTTP APIEnhancementCarts The behavior of CustomLineItems has been improved to behave more similar to regular LineItems when signing in, and when adding a new item. [API] When a customer signs in and the default anonymousCartSignInMode is used, custom line items are merged into the existing customer's cart. [API] When a custom line item is added and an equivalent one already exists in the cart, the quantity is increased.