The replenishment will run for all seasons set as default!
Replenishment Screen
Open the replenishment screen, select [all depots] and then change the seasons.
Press [x] or Exit button to exit, and the question should appear [You have amended the seasons. Do you wish to save these as the new defaults?]. Select [yes] and these will become the new defaults when you open the replenishment screen.
Replenishment Job
Open the stock analysis codes screen, and click on [season], then the button [value].
A screen with the default values should appear. Select the value, and click the box [select if this is the default for new stock codes], to either set or unset the default. Press [amend], and the row will be altered. You can have multiple default seasons, for the purpose of the replenishment, ensure only 2 are selected that match the replenishment screen.