When the collection corresponds to the season, it is said to be active. For example January 10, 2019 is included in the E19 season, on this same day it is possible to have sales of multiple collections including E19 and H18 but only one is said to be active: E19.
When a product is attached to several collections (in the context of renewal) its sales and stocks are assigned to its active collection for the day analyzed.
Example : if a product is attached to the H18 and E19 collections, its sales made during the days of the H18 season will be attached to the H18 collection and the sales of the days of the E19 season will be attached to the E19 season.
On the day of the changeover of the H18 season to E19 the remaining stocks of the H18 collection will be switched to the E19 collection. The product will therefore be considered 100% sold on the H18 collection.