We have Magento 126.96.36.199 and when you add an item with custom options to your cart, you cannot edit those options once it is in your cart. You have to delete that item and start over. Customers will not like that.
In version 1.5.x, you are allowed to click an edit button next to the items in your cart which will allow you to change any custom options or quantity without losing any data.
We might upgrade Magento 188.8.131.52 and have already set up a project at [url removed, login to view] But, the main reason we might upgrade is for the "edit" functionality in the cart.
So if you can give us the edit functionality in Magento version 184.108.40.206, then we will not have to upgrade.
Our cart is very customized and some of the core files have been changed.