The Verge claims that the powder will also eventually use algae sources, and it's still on sale now, so one would assume it's not being discontinued.

http://www.theverge.com/2015/8/3/9088407/soylent-20-bottled-...

EDIT: Ars Technica has a quote saying "We're always going to keep our powdered product around".

http://arstechnica.com/gadgets/2015/08/soylent-2-0-is-coming...