This update has a lot more fixes and improvements than the 1.036 Beta patch, including changes in the spotting system. It should work even if the Beta patch was applied, so there's no need to uninstall the game. Here's the combined 1.036+1.042 changelog:
NOTE: Savegames from older builds are not compatible.
Fix: Some units and aircraft started the battle with their maximum speed reduced even 50%. This could slow down formation movement.
Fix: The application crashed if the Battle Generator started a battle where the defending player side had bought obstacles.
Fix: The application crashed if there was an empty folder in the database directory.
Fix: The application crashed if the ISO view was run when the game window was minimized.
Fix: The Mission Editor zone painting system saved the isolated impassable 'islands' as no-go zones.
Fix: The 'Force B playable' text label without the checkbox was visible in the Battle Generator.
Fix: MILAN IFV and Marder IFV MILAN had incorrect 'ready ammunition' and 'time to fire' values.
Fix: FK 20mm AA cannons had wrong ammo (new shells for them).
Fix: The Vigilant infantry weapon had turret angle 5°.
Fix: British Jaguar GR.1 SNEB 68mm rocket muzzle.
Fix: 2x30mm ADEN tracer delay.
[campaigns] Set the 'Beyond Water' and 'Over the Hills' water type to 'Varied'.
[database] 30mm ADEN and DEFA have updated (increased) ammo consumption and number of tracers in range of other cannons with similar RoF.
[database] Deleted the excess G.91 flight.
[engine] Allow up to three friendly units to enter a map cell simultaneously.
[engine] Improve pathfinding.
[engine] Add the 'Autumn (early)' environment.
[engine] When a ground unit is firing and the enemy is trying to spot it, limit the unit's minimum size factor to the size of a 10-man infantry squad. This makes the smallest infantry teams considerably easier to spot when they fire.
[engine] Increase the gun unit (AT-guns etc.) size. This makes them easier to detect and hit.
[engine] Decrease the spotting penalty of retreating units. The units are now much less blind when retreating.
[engine] Make the standard and artillery mines harder to detect.
[engine] Increase the cost of standard minefields.
[engine] The auto-purchaser tries to buy an equal amount of minefield, AT, and wire obstacles.
[engine] Do not allow placing obstacles on rubble terrain.
[engine] Only anti-air ground units always prefer air targets.
[engine] Implement the new brush types for zone painting in the Battle Generator and the Mission Editor.
[engine] Set the default water type to 'Varied'.
[graphics] Improve the rubble graphics.
[graphics] Add new textures for the 'barren' environment plowed fields and dirt roads.
[graphics] Improve and add various new textures, zoomed-out map patterns, and pattern colors.
[graphics] ISO View: Render tree graphics in the roads/streams with trees.
[graphics] Update the main menu background texture.
[scenarios] Update scenarios: 'Walk on Water', 'Winter Desolation', 'Twin Valleys', 'East of Fulda', and 'Special Delivery'.
[ui] Implement the formation/unit 'locked' icons.
[ui] Improve the TRP graphics. Use the combined circle graphics for the TRPs, also when setting up fire missions. Use a larger selection radius for TRPs.
[ui] Render the pre-battle recon phase estimated enemy locations by using combined circle graphics.
[ui] Adjust the target line opacity.
[ui] Optimize circle rendering and adjust the dashed vs. solid line distance.
[ui] Hide the on-map mortar and artillery target text labels when zoomed-out.
[ui] Use the blue arrow to show the campaign path direction when setting it.