When you need to add a new version of an Item, change the way an Item is consumed by other BOMs, etc. here is the most straightforward way of doing batch updates. This is not hard but it does take some time (especially if it is an Item that is consumed by many other Items/products):
Steps:
Find all BOMs that consume the item you are replacing (if you are just updating the Item you will not need to update BOMs that consume that Item).
Go to the 'production' tab of the Item that consumes the Item you are adding a new version or modifying the process of consuming.
Find where the BOM consumes the Item (either in a specific routing step or in the 'Edit Items' list.
Replace the old Item with the new version or new Item
If the new Item is showing in the 'Item' list but the old Item is too, click 'Edit Items' and remove the old item
Save
Once this is done you should be able to click the 'Usage' list on the original Item details page. You should no longer see the Items where you updated the BOMs (you will see no Items if you have removed the old Item from all other BOMs successfully)