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NOW AVAILABLE: Sins of a Solar Empire II - Technical Preview 4

Published on Thursday, March 16, 2023 By Tatiora In Sins II News

Technical Preview 4 Features a Multiplayer Refresh, TEC Rebel
Gameplay Updates, Research Improvements, and More
Read the full changelog

Greetings, Sins II players! Thanks to everyone who played during our opt-in period and sent us any bug reports or weird issues that you came across. Your diligence helps us deliver the best game possible, and we're happy to let you know that Technical Preview 4 is now officially released.

Before we talk about what's in the new update, here's an important note: this update is NOT save game compatible with prior versions! This means you'll need to start fresh games to play with the features in Tech Preview 4. For the highlights in this update, read on - if you'd like more nitty-gritty details, be sure to check out the changelog at the bottom of the post.



We've made a few updates to multiplayer to keep your experience fun and running smoothly. Our new "AI Takeover" option will let you enable this preference as you're setting up your game. When selected, the AI will automatically take over for any human player who has left the game. Just as in the previous version of multiplayer, players can still jump in and take over AI spots at any time.

The new "Hotseat" option will let any other player join the game while it's running, taking over either AI players or players who have previously disconnected from the game. If you enable the new "Public Lobby" option, this means your lobby will be visible to anyone. Whenever disabled, only players who have the lobby code will be able to join.

We've also added a lobby chat so you can easily communicate with each other prior to the start of a match!


TEC Rebel Upgrades

We've added some things to the TEC Rebel faction upgrades that will spice up your gameplay a bit. Among them is the "Black Market Suppliers," which involves striking a deal with the criminal underworld for the provision of Andvar precursors to improve its fabrication rate. "Sordid Intel" will make pirates more willing to share the illicit details of their raids, while "Gang of Freebooters" will persuading pirates to add more ships to raids that you direct.

We also made a few changes to existing upgrades and improved the UI presentation of the TEC Rebel home planet's bonus, with much more yet to come!


Trade Revamp

We've changed how tradeports work! You can now add a tradeport to export specific resoruces and increase its import capacity. Adding more tradeports will increase these properties. All planets have different import and export capacities - for example, a volcanic planet might have a lower import capacity, but a high export capacity for metal.

If you have the Synergy Pact, you'll be able to export goods to other players. In the future, we may make trade its own type of agreement - we'll see how things play out! We've also added export capabilities to NPCs and added empire modifiers for trade income.



New Context Window and Game Options

On the right side of your screen, you'll notice the new context window (AKA the Empire Tree), which is populated under the following rules:

  • Your selection
  • Your camera zoom target
  • All units in the gravity well of the selection and camera zoom target

SHIFT and select to add/remove units in your selection, TAB to forward iterate your primary selection unit, and SHIFT-TAB to reverse iterate your primary selection unit. Some units like frigates and cruisers can be stacked, but not others (like capital ships).

We've added several new options for customizing your game, including:

  • Game Speed
  • Research Rate
  • Ship Build Rate
  • Hull Points
  • Income Rate
  • Disable Auction Penalties

You can also change game options when you load saved games!


Research Improvements

We know there can be a lot to keep track of, so we added a search option to the research window so you can find what you're looking for quickly. We've also added bonuses to upgrading research tiers and a compressed view to the research window for advanced players. A new research windfall system will provide one-off rewards for completing a research subject.


Haven't pre-ordered Sins of a Solar Empire II yet? No problem! There's still time to join early so that you can experience the game as it develops while sharing your feedback directly with the team behind it. Head over to to add the game to your wishlist, follow updates, and learn more about features as they are revealed. 

To read about everything included in this update, please see the changelog listed below. Thanks for playing!


Sins of a Solar Empire II Technical Preview 4 Changelog

Multiplayer Highlights

  • Added "AI Takeover" option: When enabled the AI will takeover any player that has left the game.
  • Added "Hotseat" option: When enabled any other player can join the game while it is running. They can take over either AI or other players that have disconnected from the game.
  • Added "Public Lobby" option: When enabled the lobby will be visible to the public. When disabled other players will only be able to join when given the lobby code after it is created.
  • Added lobby chat.

TEC Rebel Upgrades

  • Added "Black Market Suppliers": "A deal is struck with key figures in the criminal underworld for the provision of Andvar precursors, greatly improving its fabrication rate."
  • Includes a windfall of 2 x Andvar.
  • Added "Sordid Intel": "Pirates become more than willing to share all the illicit details of their raids. Pirates raids share vision with your empire."
  • Added "Gang of Freebooters": "Pirates are charmed by your zealousness persuading them to add more ships to raids directed by you."
  • Changed "Truce Amongst Rogues": "A deal is struck to end petty squabbling between your empire and the Pirates. Pirates will no longer attack or raid you."
  • Added "Supreme Center for Human Doctrine" - home planet bonus (15% dmg bonus for 300 seconds)
  • Added "Center for Human Doctrine" as a buildable planet component (10% dmg bonus for 240 seconds)
  • Improved UI presentation of TEC Rebel home planet planet bonus.
  • More to come!

Trade Revamp

  • Changed how tradeports work:
  • Add a tradeport to a planet to export specific resources and increase its import capacity.
  • Add more tradeports to increase these properties.
  • Planets differ by import and export capacities ex. a volcanic planet has low import capacity and high metal export capacity.
  • Players can adjust their global export priorities in the trade window.
  • You can export to other players if you have the Synergy Pact (trade may become its own type of agreement in the future).
  • Added unit item trade capabilities (ex. Argonev Trade Facilities component).
  • Added unit ability trade capabilities (ex. Akkan Mobile Trade Port ability).
  • Added export capabilities to NPCs.
  • Added empire modifiers for trade income.
  • Added sounds and errors to trade window.
  • Fixed bug with Focused Exploration being displayed with trade ports.
  • Updated various trade related strings.

Context Window Added

  • The context window now appears on the right side of the screen.
  • The context window is populated under the following rules:
  • Your selection.
  • Your camera zoom target.
  • All units in the gravity well of the selection and camera zoom target.
  • SHIFT select to add/remove units in your selection.
  • TAB to forward iterate your primary selection unit.
  • SHIFT-TAB to reverse iterate your primary selection unit.
  • Some units can be stacked (ex. frigates and cruisers) but not others (ex. capital ships).
  • CTRL-SHIFT-LEFTCLICK to stack/unstack a given unit type.
  • CTRL-LEFTCLICK click to select all units of a given type.
  • Capital ships with upgrades available will not show the standard selection backdrop as the backdrop to indicate "upgrades available" takes priority. They will still have the blue selection border.

Game Option Additions

  • Added game speed option.
  • Added research rate option.
  • Added ship build rate option.
  • Added hull points option.
  • Added income rate option.
  • Added option to disable auction penalties.
  • Added support to change game options when loading save games.

Research Highlights

  • Added bonuses to upgrading research tiers.
  • Added search to research window.
  • Research subjects that match the search filter will be highlighted.
  • The research domains (ex. military, civilian) will show a count of matching research subjects in that domain.
  • More keywords will be added in the future.
  • Added compressed view to research window for advanced players.
  • Added research windfall system: one-off rewards for completing a research subject.
  • Added windfall Focused Exploration: receive 2 Prova corvettes after completing. Also see "Black Market Suppliers" for TEC Rebels above.
  • Improved excess lab research rate bonus for higher tiers.
  • Renamed easy research time modifier to "Surplus Lab Rate Bonus”.

Gameplay - Stars

  • Added "Solar Regeneration" to stars: +100% antimatter regeneration.
  • Added "Solar Gravity Slingshot" to stars: +15% max linear speed and max turn speed.

Gameplay - Structures

  • Tied structure health/shields/antimatter to build_percentage (i.e when a structure starts building it won't instantly have full values of these properties).
  • Fixed passive regeneration being active for unbuilt units.
  • Fixed zero slot cost structures not ignoring slot availability altogether.

Gameplay - Sova Missile Battery

  • Fixed Sova Missile Battery burst pattern.
  • Fixed Sova Missile Battery firing behavior so that its point defense will only fire at missiles or strikecraft. We may eventually make this an option for any weapon.
  • Fixed name.

Gameplay - Mass Production

  • Fixed Mass Production not improving starbase self build times.
  • Mass Production now shows up on the carrier the build ships button shows the benefit.
  • Mass Production bonus is visible when going to build structures.
  • Mass Production bonus now appears when building a starbase.

Gameplay - Misc

  • Changed Garda damage to 7 (down from 10).
  • Improved auto pirate raid planet picking: will now avoid picking planets inside your empire if possible.
  • Changed reserve_squadron_hangar to be only for capital ships.
  • Fixed culture propagation not working.
  • Fixed culture resistance algorithm and update culture_resistance test cases.
  • Increased max item count to 6 at max level.
  • Fixed bug in can_increase_level when at max level.
  • Added queuing of planet items that require minimum planet level when planet is being upgraded: previously had to wait for planet to finish upgrading to minimum level, now can queue while that is in progress.
  • Added support for any player modifier to be applied to AI difficulty; instead of just bonus income rates any modifier in the game can be boosted.
  • Added support for player_exotic_factory_modifier to be scoped to specific exotics.
  • Fixed starbases not able to build garrison units.
  • Changed Human Doctrine to only work on ships (movable units).
  • Fixed starbase starting with full health if built from ship item instead of planet.

Fixed Garrison Building

  • Garrison units will now only build from idle factories as intended.
  • Any factory build time modifiers will be applied to garrison unit build times.


  • Added scenario "Pre-Alpha Large Random": 6 player scenario where the orbits of the player empires are designed to eventually collide.
  • Added scenario picker buttons that show what filter is active.
  • Added tooltip to scenario picker.
  • Added name as overlay to scenario picture.
  • Added players and teams to scenario tooltip.
  • Added pretty pictures (but temporary) for pre_alpha scenarios.
  • Disable scenario picker filter buttons if there are no scenarios.
  • Fixed scenario description going out of bounds of the window frame.
  • Fixed scenario picker filter starting on filter that has no maps and is empty.
  • Fixed scenario picture rendering not handling current dpi scaling.
  • Handled scenarios missing pictures better in tooltip: no longer render huge white square.
  • Improved pre_alpha scenario display names.
  • Tweak scenario picker window: move background components into shared window for future layout sanity, remove vertical divider and picture frame.
  • Added ability for moons to inherit their parent's orbit direction.
  • Removed suppression of saved game and scenario tooltips in list box if already selected.


  • Added Derelict structure.
  • Updated various turrets for Akkan, Dunov, Kol, and Garda to improve art, design, and firing angles.
  • Updated Akkan.
  • Updated Gauss Defense Platform.
  • Updated Autocannon Defense Structure.
  • Updated Hangar Defense.
  • Updated Marza.
  • Updated Orbital Research Station.
  • Updated Sova.
  • Updated Sova Missile Battery.
  • Updated Argonev Starbase.
  • Updated Ogrov.
  • Fixed some props.
  • Fixed some bad mesh points.
  • Fixed normals on Dunov, Sova, Derelict, Extractors, Harkka, Javelis, Sova Missile Battery, and Hangar Defense.
  • Fixed Interceptor exhaust.
  • Updated Sova Missile Battery shield.


  • Improved shadows.
  • Improved specular light.
  • Optimized some shaders.


  • Added generic player color support to particle effects.
  • Added new level up effect for capital ships.
  • Added Overcharge effect for Dunov.
  • Updated TEC exhaust effects.
  • Fixed Sova missile battery shield effect scalar.
  • Fixed some normal aliasing errors.
  • Updated Dunov Magnetic Singularity area-of-effect vfx.


  • Updated EMP Droid muzzle.
  • Updated some impact sfx.
  • Increased loudness on GenericLight HitShields.
  • Updated level up sfx.
  • Rebalanced weapon muzzle loudness.
  • Updated point defense attenuation.
  • Fixed game_client_particle effect sounds not updating their 3d position.
  • Fixed support for playing sounds with no particle effect needed for robotic frigate ability weapon "muzzle" sound.

General Misc

  • Fixed auto-scaled dpi not being able to go below 100%.
  • Fixed ALT-ENTER to toggle fullscreen not working under some circumstances.
  • Fixed player theme picker dialog not auto-closing on game start fixes.
  • Added game "tips" beside social media link buttons.
  • Added saved game contexts saved games are now bucketed into one of 6 buckets - single vs multi x (auto, quick, user).
  • Updated Player's Guide link to point to the new wiki.

Crashes and Asserts

  • Fixed assert when bandboxing lots of different units when zoomed out.
  • Fixed crash in research tooltip for research unlocking items with redirected ability tooltip rendering.
  • Fixed crash right clicking bookmarked pip group in hyperspace.
  • Fixed issues with can_make_purchase with exotics and research crash.
  • Fixed oceanic planet track pip assert: happens when upgrading track at the same time research is queued.
  • Fixed old save games potentially crashing front end background loader.
  • Fixed production window drag-and-drop crash edge case in code missing the state of dragging "started" but not "active" (mouse hasn't moved far enough) during dynamic changes in items.
  • Fixed infinite order assert.
  • Fixed crash sending pirate raid to player that has no planets now guarantees that just because a player has no planets that they haven’t "lost" yet.
  • Fixed crash caused by trade ships.
  • Fixed assert in bookmark window.
  • Fixed assert(!can_start_unmet_subject_status.is_insufficient_research_tier());
  • Fixed crash bug in selection.
  • Fixed crash when selecting dead asteroid.

Multiplayer - Misc

  • Changed in-game player name when players join games in-progress.
  • Added text color when lost to player lobby slot.
  • Fixed can't start game from lobby bug caused by dragging and dropping onto invisible team panel.
  • Fixed detection of unknown scenarios in ico server list.
  • Fixed double-click scenario picker causing duplicate game client setups if joining server.
  • Fixed initial name not being restored when players leave a saved game lobby.
  • Fixed issues loading save game lobby with dead players: shows dead players in red and can't change AI state of slot if dead.
  • Fixed joining lobby with a save game and AI player.
  • Fixed open slots not being closed for partial lobbies.
  • Force player slot to be closed if lobby is of a save game and the player has lost.
  • Improved drag-and-drop behavior in lobby window.
  • Removed gap between player slots in lobby: fixes tooltip flickering.
  • Saved picked AI player name for save game lobbies.
  • Updated player names from lobby when loading save games.
  • Fixed join game screen showing background components when no server is picked.
  • Fixed join game server list background.
  • Improved game_server_picker_list_box.
  • Fixed bug in get_joinable_slot_count.
  • Fixed bug of joining players getting duplicate player colors as other slots.

User Interface - Research

  • Added breakdown of where research is coming from in empire research tooltip similar to economy breakdowns.
  • Added gap between research tooltip picture and titles.
  • Added support for research subjects to provide alliances to NPC players. ex. ally with pirate in late game for share vision.
  • Added research provided to build structure tooltips: previously was just on ship building tooltips so wouldn't show up for TEC orbital research center.
  • Added research text filter tooltip to domain buttons.
  • Fixed always showing exotics required: looks wrong to show exotics required for complex purchases when they are further down the chain and not root costs. For example, the Hakka heavy cruiser at start of the game was showing exotics required because it needs research that needs tier that needs exotics but the ship itself doesn't need them.
  • Fixed gunship corvette tooltip was getting value offset corrupted by huge research name: now there is an exception for research required.
  • Fixed research domain tooltip too long in some circumstances.
  • Fixed tier 1 research tooltips not showing tier required.
  • Improved all tooltips with purchase details: consistently break down errors into research required, exotics required, generic error.
  • Added new batch of research pictures.
  • Improved empire research tooltip.
  • Improved empire research tooltip at start of game shows description that structures/components need to be built.
  • Improved research lab description.
  • Improved research provided tooltip for orbital research: now uses the modifier tooltip so looks the same as planet component items.
  • Improved research required tooltips: show tier on same line and show different header for tier only.
  • Improved research tier tooltip: research produced converted to table format similar to structure slots in build structure tooltip.
  • Improved the upgrade and improve blocks in research tooltip.
  • Fixed up cooldown/reload rate research descriptions.
  • Improved layout of research window text filter and compressed view button.

User Interface - Diplomacy

  • Added can_pick_player_alliance_offer_planet_query: picking of planets now have more informative error messages and better logic. (ex. must be owned by the relevant alliance offer player)
  • Added current alliance state to player tooltip.
  • Added description of why alliance offer can't be opened again after offer is sent.
  • Fixed alliance offer chat tooltip going off the screen.
  • Fixed unable to break alliances when other player has lost.
  • Improved alliance lock duration tooltip.
  • Improved alliance lock tooltip: now differentiates between time extensions and initial lock to avoid confusion.
  • Improved pick alliance offer: planet main view interface now fade out planets that can't be picked.
  • Improved alliance offer window: show player tooltip (previously was only in the root diplomacy window).

User Interface - Misc

  • Added explicit pause and change game speed buttons to the top bar.
  • Added CTRL guard to prevent accidentally removing structures in the buildable structure area.
  • Changed unit renaming: in order to prevent issues with being able to select or focus on a unit, the rename feature now requires a hold of the mouse button to activate the rename text field.
  • Improved pick_alliance_offer_planet_cursor.
  • Added "Orbit" to civilian and military slot strings help differentiate from surface slots.
  • Added delete saved game button.
  • Added double click support load game windows.
  • Added exotic count to toggle exotics window button.
  • Added extra_text_filter_strings.
  • Added is_change_time_scale_disabled_description.
  • Added new exotic market portrait.
  • Added new market portraits.
  • Added planet level to planet picture.
  • Added player visuals (colors/icons/portrait) saving when joining and creating games - will attempt to apply last saved visuals.
  • Added ship level to ship window picture.
  • Changed negative red color.
  • Fixed bounty button layout.
  • Fixed buying items in empire windows not showing all items.
  • Fixed error in culture_resistance_rate summary calculation.
  • Fixed forced uppercase text box being bypassed when pasting in text made it error prone to share game codes (must be uppercase). Also, allowed bypassing the ship/planet name restriction of all caps.
  • Fixed icon only top bar buttons not having highlighted state.
  • Fixed l keybinding not being lowercase.
  • Fixed missing planet bonus strings.
  • Fixed production window not showing up if unit was selected on ownership changes.
  • Fixed save game file picker showing false negative warnings for exe size.
  • Fixed spelling of icon.
  • Fixed unit bars not handling units with no health (derelicts) were showing empty black bars.
  • Fixed unit name text entry stuck in dragging selection mode.
  • Fixed unowned and NPC planets showing planet level 0 on HUD.
  • Improved algorithm for fading out arrows during text filtering - previously some arrow segments were being rendered when they shouldn't have been.
  • Improved and clean up list box styles now has nice hover state for not selected.
  • Improved HUD top bar layout.
  • Improved player theme picker UI.
  • Improved text alignment of delta assets - now lines up with current assets above them in the top bar.
  • Removed claw background from front_end_listbox_background makes it hard to piece components together in front end when they are baked into the background brush.
  • Removed retrofit bay description duplicate of ability descriptions.
  • Used newer main view icons for HUD monochrome icon.
  • Fixed Targeting Array Prototype extra quotes.
  • Fixed inconsistent unit names: moved the garrison prefix to the player name instead of changing the unit name.
  • Fixed plural of military slots required.
  • Fixed factory rally point lines showing up at start of game.
  • Revised hud_planet_window_model to handle stars.
  • Improved planet components ordering.
  • Added improved main view icon backgrounds and borders.
  • Added optional notification fills for units with buffs (e.g. Human Doctrine buff).
  • Renamed "buy ships/orbital structures" to "build ships/orbital structures".
  • Fit more notification cards under top bar.
  • Added "has lost" to the saved game preview of players.
  • Added saved game picker picture and info for selected saved game.
  • Added settings to save desired context when picking saved games (quick/auto/user). There are two different settings, one for single-player flow, one for multi-player flow.
  • Fixed single player load game button text case not consistent with other action buttons.
  • Improved auto and quick save list rendering: now more readable with nicer formatting.

User Interface - Tooltips

  • Added advanced tooltip view by pressing ALT when hovering over a unit to build or research to start. Removes overwhelming newer players with too much information (ex. hull, armor, build time, research time, unit health).
  • Added bottom bar frame tooltip anchor tolerance.
  • Added carrier squadron capacity to build ship/structure tooltips.
  • Added exotic factory details to tooltip.
  • Added owner_unit_ability tooltip line rendering to unit items.
  • Improved join button tooltips.
  • Added tier modifiers to tier tooltip.
  • Added time and player state to saved game header allows more details in saved game picker window tooltip.
  • Added tips window - remove structure tooltip describing right click to remove as it is now a tip.
  • Added tooltip for exotic factory count.
  • Added tooltip for how to remove structures.
  • Added tooltip for toggle compressed view button.
  • Added tooltip to saved game picker.
  • Added unit type name to tooltip ex. Kol battleship.
  • Fixed empty "active actions:" block in some tooltips ex. Argonev starbase.
  • Fixed jitter in derelict capture time remaining tooltip upon being captured.
  • Fixed planet health bars showing up in tooltip header for unowned planets.
  • Fixed player slot dragging tooltip showup up for non-hosts.
  • Fixed tooltip add_horizontal_gap_to_value.
  • Fixed tooltip not showing adjusted exotic build time.
  • Fixed tooltip overlapping main view too much.
  • Fixed tooltips showing up with hide user interface.
  • Fixed unit name text entry blocking tooltip for bottom bar picture.
  • Fixed unit_group_tooltip_builder not handling some unit types nicely (ex. star).
  • Improved ability tooltips and buttons: don't show status icon when ability not leveled up, convert experience level required to standard "failed query" style, remove upgrade title.
  • Improved all tooltips with purchase details.
  • Improved build extractor tooltip: now free asteroid has same styling as other top level hard errors and shows extraction rate.
  • Improved color of remove structure tooltip description.
  • Improved derelict loot tooltip: distinguishes between capture time and time remaining and groups experience and reward together.
  • Improved failed query tooltip when no available item slot.
  • Improved handling of empty tooltip descriptions.
  • Improved NPC tooltip: make all sub-category headers consistent, no icon.
  • Improved NPC tooltip: make all sub-category headers consistently upper-case.
  • Improved planet maintenance tooltip.
  • Improved price is free: now built into the purchase details tooltip instead of an extra isolated section.
  • Improved ship factory tooltip details: now multicolumn and has more consistent header.
  • Improved structure slots in tooltip: more compact and readable with columns - when slots are required conforms closer to new failed queries display.
  • Improved supply tooltip: now more consistent with other queries when insufficient supply. The line itself adjusts label and color instead of having a redundant generic failed query block put on top.
  • Improved tooltip when exotics required.
  • Improved tooltip when exotics required like research required: don't show the entire purchase cost table when the player can't build exotics.
  • Improved weapon tooltip: first column now aligns with other values.
  • Removed culture center description duplicate of ability description as it is already shown on tooltip.
  • Removed some old tooltip pictures.
  • Removed valid planet types in item tooltip: instead planets that are unowned now show what planet components they could support.
  • Hid abilities that are not researched - simplifies tooltips at start of game.
  • Improved ship factory header.
  • Fixed capital ships showing up in research summary tooltip as providing 0 points.
  • Improved tooltip overlap detection and handling.
  • Fixed ship modifiers bloat in late game tooltips by adding analysis icons in the ship window to break down the categories: weapons / defense / abilities.
  • Fixed unit modifiers being duplicated on the unit tooltip. ex. Human Doctrine on rebel starting units would show +15% weapon damage twice.
  • Merged and sorted weapon modifiers into a more compact form.
  • Moved all mobility modifiers to the move action button tooltip.
  • Moved all carrier modifiers to the toggle carrier button tooltip.
  • Improved tooltip item abilities details:
  • If the item contains both passive modifiers and active action a sub header will exist for both groups.
  • Active action details now has a line for what unit will be built (so deploy starbase item active action isn't empty).
  • Made Inspiring Broadcast buff visible on ship tooltip.
  • Moved ship armor and shield mitigation to advanced tooltip view (press ALT).