Overview
This article explains how Boostmyshop can manage stock level for kit products.
Boostmyshop calculates the stock available for kits based on the children stock level, using the smallest quantity available among children products.
Enable kit stock management for warehouse
First you need to enable the kit stock management for the warehouses. Select menu inventory > warehouses, go in your warehouse and enable calculation :
At this stage, any stock changes for children product will automatically update the stock for the kit product.
Run a first manual update
You must run a manual update to update kit stock available for existing kits.

Note : this must be done only when you enable the option in the warehouse, it is not needed later when you create new kits or update kit content.
To manually update kit stock levels, go in menu inventory > kits, and click on button "Recalculate kit stocks" :
Enable export to Prestashop
By default, Prestashop integration pushes only stock for simple products, not for Kits.
To enable the option, go within the Prestashop integration, select tab "Configuration" and scroll down until section Stock level export settings, then enable option :
After enabling this option, manually run a stock check from the same screen, in tab "Feeds":
Enable export to Magento / Shopify

This option does not exist yet for Shopify or Magento.