March 2011 patch is a major patch to that was published in March 2011. The following is a list of changes as announced by Civilization V 2K Games.
Significant turn time improvements.
Invisible Rivers now display correctly. This caused many issues because the player could not see some rivers, like fresh water showing up in strange places, unit movement suddenly shortened, etc.. Basically, there were certain rivers that did not display where forks occurred, etc.
Memory leak – UI – Change the way the UI Manager calculates the hash of a texture so that different ways of specifying the same texture will not load the same texture more than once.
Memory leak – DLL – Fix memory leak in DLL Args system
Crash/Turn Spike Edit
Correct coding error that could cause turn-time spikes, incorrect deployments for protected bombard attack, or incorrect deployments as armies marched across the map
User Interface Edit
Add combat summary when a city bombards a unit
Add a new diplomatic status "Denouncing" that displays on the turn that an AI civ is denouncing the player
Embarked units no longer look like they have 500 strength
User warned if about to declare war on a city state that is under protection of a major power
Taper off benefit of excess food when building settlers
City-States now recognize when a road is connected for their road-connection quest.
Golden Ages now provide +20% production per city rather than +1 hammer per tile
Strategic AI Edit
Prevent AI from building too many AA units
Don't allow CSs to build Manhattan Project
AI calculation of enemy military might are tweaked based on size of enemy gold reserve
AI calculation of enemy power now takes into account promotions
Diplomatic AI Edit
Avoid cascades of denunciations against a single player. AI now uses its own current friendliness level with a given power to determine how much weight to place on a denunciation against that power.
Denounciations expire after 50 turns
Declarations of Friendship expire after 50 turns
Added support for policies that provide culture from kills
Added support for policies that provide extra culture from cultural improvements
Added support for policies that provide extra embarked movement
Added support for policies that provide free Great People
Online Panel now displays TOTAL downloads for a mod and not just the downloads for that specific version.
When you click on a mod in the online browser, you may now use a dropdown to select a previous version.
Added Line Control for modders to use when creating graphs, etc.
Can now use DLC civilizations in multiplayer
Added Ring, Skirmish and Ancient Lake maps to MP.
Bug Fixes Edit
Clear up cases where diplomatic status could show as "Friendly" even after that AI power has denounced the player.
Fix situations where AI demeanor and verbiage didn't match friendliness level shown in diplomatic status string.
Additional bug fixes and tweaks.
Balance Changes Edit
Game Rules Edit
Cities must now have three or more tiles in between them (1 more tile than before), unless separated by a sea/coast tile.
Cities now only get 1 free production and 0 free gold (1 less in both cases)
Trade routes get bonus gold based on population of capital; formula changed a bit so minimal gold received for hooking up very small cities
Bonus production from excess food (used when building settlers) tapers off if excess is 3 or more.
Allied maritime city states provide 3 food per turn to the capital, not 4
Balance pass on production and maintenance costs throughout the game.
Aqueduct added (entirely new building). 40% of Food is carried over after a new Citizen is born.
Palace boosted to 3 gold and 3 production
Granary gives bonus 1 food for Wheat/Banana Deer; cost reduced
Market and Bazaar provide 2 gold (as well as +25%)
Workshop provides 2 production (bonus reduced to +15% but affects ALL production); cost increased
Windmill now has a +15% production modifier (for buildings only) and provides 2 production
Stable gives bonus 1 production for Sheep/Cattle/Horse and can be built with Sheep or Cattle; cost reduced
Lighthouse gives bonus 1 food for Fish; cost reduced
Ironworks dropped to 8 production (but earlier in tech tree now)
Factory requires Workshop; add 3 production but boost now just 25%; has 1 more specialist slot (now 2)
Nuclear and Solar Plants now require Factory but increase to production is now 35% and provide 4 production themselves; these two now mutually exclusive
Hospital adds 5 food (but no longer retains food), requires Aqueduct
Forge adds +1 production to each source of Iron
Reduced Armory maintenance to 2 gold
Reduced Colosseum happiness to 3, and reduced maintenance to 2 gold
Reduced Theatre happiness to 4
Reduced Monastery maintenance to 0 gold
Reduced Garden maintenance to 1 gold
Reduced Observatory maintenance to 0 gold
Reduced Opera House culture to 4, and reduced maintenance to 2 gold
Removed the Great Person Point from Public School
Specialist Adjustments Edit
Tradition: Culture border expansion discount in cities placed on Tradition branch opener. Discount increases over the course of the game. Also grants +3 Culture in the capital.
Aristocracy: Wonder bonus reduced by 5% to 20%.
Legalism: Provides a free Culture building in your first 4 cities.
Oligarchy: Garrisoned units cost no maintenance, and cities with a garrison gain +100% ranged combat strength.
Landed Elite: +15% Growth, and +2 Food per city.
Monarchy: +1 Gold and -1 Unhappiness for every 2 Citizens in your capital.
Liberty: +1 culture per turn in every city.
Collective Rule: Settler production increased by 50%, and a free Settler appears near the capital.
Citizenship: Worker construction rate increased by 25%, and a free Worker appears near the capital.
Representation: Each city you found will increase the Culture cost of Policies by 33% less than normal. Also starts a Golden Age.
Order: Reduce Order production bonus to 15%.
Meritocracy: +0.5 Happiness for each city connected to the capital, and a free Great Person of your choice appears near the capital.
Fish reduced to 1 food (but can be boosted back to 2 with Lighthouse)
Marble boosts wonder production by 20%, down from 25%
Colossus no longer goes obsolete
Angkor Wat now provides a 25% discount for the costs (both culture and gold) to gain plots empire-wide.
Civ Unique Bonuses Edit
Reduce Chu-ko-nu from 10 to 9 ranged strength
Doubled culture from kills for Aztecs
Krepost now provides a 25% discount for the costs (both culture and gold) to gain plots in the city.
Paper Maker only provides 2 gold but no longer requires any building maintenance
Map Generation Changes Edit
Increased Oil quantity per resource.
Minimum Uranium is now 2.
Cut Deer appearance in arctic regions.
Adjusted Sheep placement so it is more spread out.
Decreased Wheat appearance in Plains.
Increases Cow appearance overall, including adding up to 2 Cow tiles to heavy grass start positions.