Currently, the playtest of the legacy pre-alpha build is no longer active on Steam. There are plans to conduct another playtest with the new networked build with the primary focus of testing core networking elements. More information will be communicated when this build is nearing a ready-to test state.
A reminder - The objective of the pre-alpha/alpha programs is to deliver and improve early versions of the game in a phased base approach. Each phase includes a limited scope of playable game features over a specified duration of time.