Stellaris 4.5 'Cygnus' Open Beta 2 Arrives Early with Save-Breaking Pop Overhaul

Paradox Development Studio pushed the second update to the Stellaris 4.5 'Cygnus' open beta ahead of its planned release date, citing QA tests that completed faster than expected. The update is live on the stellaris_test_4.5 branch and incorporates all changes from version 4.4.5.

What changed

The headline alteration is a breaking change to pop group architecture — existing saves will not be compatible.

• Pop groups are no longer divided by ethics or factions; instead, each group carries a percentage share belonging to each faction or ethic.
• Ethics and factions are now visible directly in the planetary management UI, with tooltips for attraction values and verbose breakdowns available by holding Alt.
• Pops shift ethics and factions more frequently; faction conversion and ethic attraction both affect faction growth.
• Faction randomization logic has been simplified.
• Cyberization policies have been updated to reflect the new pop structure. The Limited Cybernetic species trait is removed; under the Limited Cyberization policy, Cybernetic Spiritualist pops no longer benefit from Cybernetic Job Efficiency. The Limited Cyborg leader trait is unchanged. The Approval penalty from the Flesh is Strong demand is also reduced.
• The Knights of the Toxic God origin is now unlocked for nomads.
• A new Fleet Doctrine policy offers six doctrines governing the tactical roles ship classes are designed to fill, influencing automated designs and auto-complete.
• New Weapon Preference, Defense Preference, Starbase Weapon Preference, and Starbase Defense Preference policies give players and AI finer control over automated ship and station designs.

Players testing the beta should expect to start fresh saves; in exchange, they gain meaningfully more transparency and control over both population politics and fleet automation.