I'm working with a private app and I need permissions for read_publications, because I know the id the sales channel of my Store. Shopify support tell me that I need a private plus app for getting this permissions. How can I convert my private app in private plus app? Thanks.
I believe the destination shop that installs your app needs to be on the Shopify Plus Plan. I'm not sure if a test development partner shop is assumed as being Plus-compatible or now. Perhaps others on this board can chime in as to that.
I think it, that a plus store could be partner plus but Shopify has separate it because developer and merchants are two different roles, The first require special features for selling and another require special features for developing.