IMDbPro has updated to add Elara Pictures as the production company.  According to Deadline back in April 2014:

“Heaven Knows What is the first feature under the Safdies’ Elara Pictures production banner, which the duo launched with partners Sebastian Bear-McClard and Oscar Boyson. Elara is set to produce multiple indie features per year, committed to giving complete creative control to each project’s director”.

Info was also included in the latest issue of Production Weekly via:

“Prod Weekly (Issue 954 preview, July 16th) shows a Sept 2015 start of production, no location or other cast listed as of yet”