To participate:

1. right click on the game in steam
2. click on properties
3. click the "betas" tab
4. the drop down menu will have latest_experimental available ← you want THAT
5. select that and wait for the game to download.

Changelog A20.1 B5:

Added 

• Show Stability makes a clearly different green for max and darkens colors every 1m of world space 

Changed 

• Updates to downtown_strip_05 based on player feedback (e.g. texture issues, sleeper adjustment, etc.)
• Updated to house_modern_18 made path more obvious, added torches, added triggers so sleepers aren't left behind, etc.
• Updates to remnant_skyscraper_01 based on QA feedback. 
• Updated house_construction_01 and house_construction_02 with new art props 
• Updated remnant_business_0205, updated with new art and shapes 
• Updated store_book_01, store_clothing_01, store_electronics_02, store_grocery_01, store_gun_02, added new art and new shapes 
• House_modern_23 Changes made based on feedback 
• Updated restore power and sleeper configuration for countrytown_business_04 based on player feedback. 
• Warehouse_04: added floor trims inside warehouses, fixed mispainted textures in bathrooms and kitchen's floor, replaced shelfs to prevent z-fighting. 
• Remnant_waste_01 replaced sinks for sink shape inside ice cream store. Improved destroyed ceiling 
• Updated downtown_strip_10 based on player feedback. 
• Downtown_filler_27 removed door frame simulating door that was permanently closed to avoid confusion 
• House_modern_23: changes made after level designers meeting feedback 
• Reworked all couch harvests to give some of the main resources on the destroy event instead in the middle of the harvest 
• Slightly increased the probability of books found in book piles and crackabook shelves 
• Enabled graphics jobs 
• Downtown_filler_23. Replaced bank upper windows for bulletproof. Replaced old fuse boxes. Fixed trigger not properly linked to door. 
• Updated loot probability and quality templates to better align with the new loot stage system 
• Added and updated loot probabilities with a ProbT2Cap template to prevent empty loot containers and/or missing loot items at high loot stage where ProbT3 is not available 
• Mailboxes now have a higher chance to spawn archery, spear, and needle and thread books early game 
• Reworked tiered chest loot to better reflect POI difficulty 
• Reduced the amount of aloe cream found in backpacks 
• Increased the chance to find acid in sinks and chemical sets 
• Added another low chance to find vehicle wheels in Pass-N-Gas crates 
• Warehouse_04:  final loot room sleepers volumes rearranged to hold at least two feral. Replaced fake scrap metal rollup doors for steel ones. Fixed mispainted texture in perimeter wall )
• Reorganized the furniture helpers to prevent unwanted block rotations hiding adjacent block faces due to mixed block types/properties 
• Moved cabinets, cupboards, and bookshelves to a new player crafted helper block (same recipe as before) 
• Moved the storage crate and writable storage crate to their own recipes (same recipe as before) 
• Moved the old chair out of the furniture helper and gave it its own new recipe 
• Added produce baskets, pallets, and empty clothes shelves to furniture helper 
• Updated preview thumbnail JPGs for part_loot_t1 through t5. 
• Updated  house_old_tudor_06 to new RWG standards. 
• Updated  house_old_bungalow_08 for new RWG country residential.
• Updated large_park_01  moved kiosk 1 block to the back, added extra floor under it 
• Farm_04 made changes so it's no longer easy to reach and kill final sleepers before triggering. Fixed mispainted textures. Changed quick exit for roll up door. 
• Farm_08 locked front door. Added light pointing at the quest's entrance. 
• Removed restore power quest from lot_downtown_filler_01 
• Cut Game Stage Achievements in half 
• Penetrator Perk now references the Lever Action rifle instead of the Marksman rifle 
• Updated Localization for furniture helper blocks 
• Drone description no longer references the ability to fight
• Reduced ammo loot counts by ~15 to 30% 
• Reduced amount of ammo found in yellow zombie loot bags from large to medium group 
• Reduced amount of ammo found in blue zombie loot bags from 2 large rolls to 1

Fixed 

• Remnant_downtown_12, mispainted textures 
• Terrain density covers satchel in warehouse_04 
• Missing paint behind curtains in house_old_ranch_01. 
• Missing paint in gas_station_07. 
• In body_shop_01, loot room sleepers on rooftop spawn within players view 
• Terrain water blocks can be broken and sent flying in block shape by the splash damage from Rocket HE rounds. 
• Distant and/or low resolution reflections/lighting on arrows are pink 
• Inaccessible cabinets in house_old_ranch_06. 
• In POI oldwest_business_12 sleeper stuck between 2 bookshelves. 
• In POI house_old_victorian_05 nightstand and bed clipping into window ledges. 
• House_old_modular_06 z fighting on exterior. 
• Diner_03 density issue on roof. 
• Diner_03 bathrooms need stall art update (restaurant booths, commercial sink, mirror, easy exit, etc.) 
• House_old_modular_08 z-fighting on exterior windows 
• POI canyon_gift_shop has extra blocks. 
• Survivor_site_09 z-fighting on watch tower. 
• Fastfood_04 terrain hole under car. 
• Treasure maps calculate location from 0,0 
• Confuse does not affect vehicle controls. 
• Drone can fall under bedrock and get stuck 
• Junk Drone stay command sync error with clients that could cause multiple drones. 
• Remove the "and fight" from the Robotic Drone's information localization 
• Junk Drone case where teleporting away was not creating a nav object for the unloaded chunk. 
• Handled a case where picking up the junk drone was not fully cleaned up from the player data. 
• NRE caused by highlighted text in inventory search field 
• UI button hover scale effect only playing once per button per game session 
• Playtest and give feedback on countrytown_business_13 The Dead Rooster 
• HUDStatBar not working with "statcurrent" for "ActiveItem" when holding a paintbrush 
• Playtest and give feedback on countrytown_business_06 Ruby's 
• Downtown_filler_30 (TIER3, clear, search): sleepers showing through ceiling and birdnest clipping through awning 
• Workbench not crafting multiples of items correctly if output slots full and placed directly into player inventory. 
• Workbench duplication bug 
• Can not shoot through bunkBedFrame 
• Pathing incorrect ladder height check if open to sky 
• SMG and Desert Eagle  holosight location update. 
• Adjusted collision to close out gap between the door and the frames of all cellar doors and shutters that allowed player interaction behind them 
• Inconsistent resources and scaling on military armor recipes 
• AK47 and Pump Shotgun  holosight location update. 
• Tactical AR  holosight scope offset for dot alignment. 
• Holosight dot position updates for Iron Crossbow and Compound Crossbow 
• Holosight dot position updates for Lever Action Rifle and AutoShotgun 
• Structural Integrity is not recalculating when block pillar is recreated 
• Slightly tweaked Scope Camera offsets and dot placement for Reflex scope on pipeShotgun 
• Playtest and give feedback on countrytown_business_13 The Dead Rooster 
• Missing textures and sleeper volume issues in downtown_filler_13 based on player feedback. 
• Sniper Rifle  holosight dot update. 
• Attempting to generate a world with Seed: ActableCravings results in a KeyNotFoundException 
• Scrolling too fast in part selector causes NREs 
• Show Stability could show old colors 
• Playtest and give feedback on commercial_strip_01 
• Using Advanced Generation to generate a 4k world results in an Argument Out Of Range Exception 
• Cellar door and shutter open/close issue 
• Explosion of water fix would cause chunk regen to never resume 
• ChangeBlocks handling of clusters with recursion 
• Farm_07  mispainted texture in kitchen cabinet next to stove 
• Achievements aren't working 
• Switching between Steam offline mode and online within one save game results in different player profiles/saves 
• Restore power host melee desync 
• Z-fighting on exterior windows at house_old_bungalow_11. 
• In POI motel_01 sleepers in final room do not spawn until after player is inside room 
• Door unlocked in house_old_victorian_01 
• House_mansard_06 unstable cellar door 
• Z-fighting and missing paint at POI bank_01 
• Exit sign in courthouse_med_01 is too low. 
• Floating TV's in bank_01. 
• Bank_01 z-fighting 
• Action_time_shift index out of range. 
• Using Twitch teleports while in a workstation UI does not close the UI. 
• Added missing IndexName property for chandelierLight to work with restore power quests 
• Origin shift could cause objects to fall through world 
• Vehicles and drones are using repair kits without showing the minus inventory icon on the HUD
• Path node otherheight bad in cabin_11 

Source: Changelog A20.1 B5