Astro Colony opens multiplayer reliability test on Steam branch mptest

Astro Colony has opened public testing for a major multiplayer reliability update on Steam. The custom mptest branch (password: testmulti123) is live now, with the official release expected in about two weeks. The update is aimed at keeping the game playable on rough connections, including around 500 ms of latency or 25% packet loss.

• Syncing no longer relies on Begin Play; it now waits until all systems are fully replicated, making eventual synchronization effectively guaranteed.
• Client simulation gets two correction types. If resources were pushed in the wrong direction, the whole wrongly pushed chain is teleported back. If the client is behind and pushes are waiting, the server overrides the simulation to resynchronize; in the saving situation where the server removes a conveyor belt, resources still move as if the belt were there.
• Every resource now has a server-set unique ID, making it easier to find and correct exact positions and preventing accidental removal of moving resources in adjacent cells.
• A new junction system improves stable merges and keeps client and server states matching. Devices and logic blocks now create conveyor connections, and their gates show belt connections like normal placement.
• Nebulas are visible on clients.
• A new in-game sync option syncs all existing planets and their states.
• Resources are still simulated locally, with junctions and logic-block controls helping keep the state in sync.
• Miners are fully server-controlled to ensure valid moves and avoid ghost resources.
• Crafting now refunds resources from active recipes when a device is removed.
• Asteroid interactions have a new sync system.
• Visual and audio cues, like the no-oxygen warning, now trigger correctly on clients.
• Players who left a station in a previous universe are no longer linked to it and won't move with it.
• Cosmic events, vehicles, and other gameplay systems pause while a new player joins.

• Fixed an Unreal crash tied to hair simulation and entering the map, plus another crash from cleanup and manual component destruction; rendering is now cleaned up by the engine.
• Animals and geysers now appear correctly in multiplayer after first-time generation.
• Clients can place the colony origin block again, and the standing animation after receiving oxygen works on clients.
• AI no longer registers multiple times in the UI.

• Auto-syncing detection is missing: the plan is for the game to flag invalid states and either prompt players to sync or handle it in the background.
• Pipes and ramps still need testing, along with splitters and filters/blockers at 1000 ms latency.
• Large data replication, such as blueprint limits, needs more testing.
• The racing mod isn't performing as it did before the new initialization.

Feedback and discussion are on the official Discord: https://discord.com/invite/EFzAA3w