Next-Generation Planetscope imagery will now be published as both standard and test quality. 3 and 4 band data will be available through the existing PSScene3Band, PSScene4Band, and PSOrthotile items. Additionally, 5-band (blue, green, red, rededge, nir) imagery is available under the analytic_5b asset, which is in the PSOrthotile item type. The way to identify data in this release is by the "psb.sd" value in the "instrument" field.
See https://developers.planet.com/docs/data/items-assets/ for details on Items/Assets.
An Image Quality Report on data contained in this release is available at https://assets.planet.com/docs/Planet_Combined_Imagery_Product_Specs_letter_screen.pdf.