Looking at Amalfi - Positano - Sorrento route schedule I see it’s mentioned it’s valid until 31st of March. What happens then? How far in advance will the new schedule be posted?
The schedule will be updated, getting ready for the tourism season, being a bit more frequent and running later as well. It will expand a bit compared to the low-season schedule.
The Amalfi-Positano-Sorrento route is the most busy, the most trafficked SITA route on the Amalfi Coast.
As to when it will be posted, I believe on the same day. If it comes to the need of ahead planning, plan using the current schedule knowing that you will still have the same options if not more.