diff --git a/AI/BattleAI/BattleAI.cpp b/AI/BattleAI/BattleAI.cpp
index a997ea4fb..753375b1b 100644
--- a/AI/BattleAI/BattleAI.cpp
+++ b/AI/BattleAI/BattleAI.cpp
@@ -179,7 +179,7 @@ BattleAction CBattleAI::activeStack( const CStack * stack )
 	}
 	catch(std::exception &e)
 	{
-		logAi->errorStream() << "Exception occurred in " << __FUNCTION__ << " " << e.what();
+		logAi->error("Exception occurred in %s %s",__FUNCTION__, e.what());
 	}
 
 	return BattleAction::makeDefend(stack);
@@ -268,7 +268,7 @@ void CBattleAI::battleStacksRemoved(const BattleStacksRemoved & bsr)
 
 void CBattleAI::print(const std::string &text) const
 {
-	logAi->traceStream() << "CBattleAI [" << this <<"]: " << text;
+	logAi->trace("CBattleAI [%p]: %s", this, text);
 }
 
 BattleAction CBattleAI::goTowards(const CStack * stack, BattleHex destination)
diff --git a/AI/StupidAI/StupidAI.cpp b/AI/StupidAI/StupidAI.cpp
index 57f610ca0..207f0e357 100644
--- a/AI/StupidAI/StupidAI.cpp
+++ b/AI/StupidAI/StupidAI.cpp
@@ -261,7 +261,7 @@ void CStupidAI::battleStacksRemoved(const BattleStacksRemoved & bsr)
 
 void CStupidAI::print(const std::string &text) const
 {
-	logAi->traceStream() << "CStupidAI [" << this <<"]: " << text;
+	logAi->trace("CStupidAI  [%p]: %s", this, text);
 }
 
 BattleAction CStupidAI::goTowards(const CStack * stack, BattleHex destination)
diff --git a/AI/VCAI/AIUtility.cpp b/AI/VCAI/AIUtility.cpp
index fcad28339..aee7ee37e 100644
--- a/AI/VCAI/AIUtility.cpp
+++ b/AI/VCAI/AIUtility.cpp
@@ -339,7 +339,7 @@ bool isSafeToVisit(HeroPtr h, crint3 tile)
 	{
 		if(heroStrength / SAFE_ATTACK_CONSTANT > dangerStrength)
 		{
-			logAi->traceStream() << boost::format("It's safe for %s to visit tile %s") % h->name % tile;
+			logAi->trace("It's safe for %s to visit tile %s", h->name, tile());
 			return true;
 		}
 		else
diff --git a/AI/VCAI/AIUtility.h b/AI/VCAI/AIUtility.h
index 1216ef9f1..46d59ad2c 100644
--- a/AI/VCAI/AIUtility.h
+++ b/AI/VCAI/AIUtility.h
@@ -42,7 +42,7 @@ struct HeroPtr
 public:
 	std::string name;
 
-	
+
 	HeroPtr();
 	HeroPtr(const CGHeroInstance *H);
 	~HeroPtr();
@@ -105,7 +105,7 @@ struct TimeCheck
 
 	~TimeCheck()
 	{
-		logAi->traceStream() << boost::format("Time of %s was %d ms.") % txt % time.getDiff();
+		logAi->trace("Time of %s was %d ms.",txt,time.getDiff());
 	}
 };
 
diff --git a/AI/VCAI/Fuzzy.cpp b/AI/VCAI/Fuzzy.cpp
index fac28819a..707aea2c3 100644
--- a/AI/VCAI/Fuzzy.cpp
+++ b/AI/VCAI/Fuzzy.cpp
@@ -46,7 +46,7 @@ engineBase::engineBase()
 void engineBase::configure()
 {
 	engine.configure("Minimum", "Maximum", "Minimum", "AlgebraicSum", "Centroid");
-	logAi->infoStream() << engine.toString();
+	logAi->info(engine.toString());
 }
 
 void engineBase::addRule(const std::string &txt)
@@ -149,7 +149,7 @@ void FuzzyHelper::initTacticalAdvantage()
 		{
 			fl::Rectangle* none = new fl::Rectangle("NONE", CGTownInstance::NONE, CGTownInstance::NONE + (CGTownInstance::FORT - CGTownInstance::NONE) * 0.5f);
 			ta.castleWalls->addTerm(none);
-                    
+
 			fl::Trapezoid* medium = new fl::Trapezoid("MEDIUM", (CGTownInstance::FORT - CGTownInstance::NONE) * 0.5f, CGTownInstance::FORT,
 				CGTownInstance::CITADEL, CGTownInstance::CITADEL + (CGTownInstance::CASTLE - CGTownInstance::CITADEL) * 0.5f);
 			ta.castleWalls->addTerm(medium);
@@ -160,7 +160,7 @@ void FuzzyHelper::initTacticalAdvantage()
 			ta.castleWalls->setRange(CGTownInstance::NONE, CGTownInstance::CASTLE);
 		}
 
-		
+
 
 		ta.bankPresent = new fl::InputVariable("Bank");
 		ta.engine.addInputVariable(ta.bankPresent);
@@ -201,7 +201,7 @@ void FuzzyHelper::initTacticalAdvantage()
 	}
 	catch (fl::Exception & pe)
 	{
-		logAi->errorStream() << "initTacticalAdvantage " << ": " << pe.getWhat();
+		logAi->error("initTacticalAdvantage: %s", pe.getWhat());
 	}
 }
 
@@ -262,7 +262,7 @@ float FuzzyHelper::getTacticalAdvantage (const CArmedInstance *we, const CArmedI
 	}
 	catch (fl::Exception & fe)
 	{
-		logAi->errorStream() << "getTacticalAdvantage " << ": " << fe.getWhat();
+		logAi->error("getTacticalAdvantage: %s ",fe.getWhat());
 	}
 
 	if (output < 0 || (output != output))
@@ -273,7 +273,7 @@ float FuzzyHelper::getTacticalAdvantage (const CArmedInstance *we, const CArmedI
 
 		for (int i = 0; i < boost::size(tab); i++)
 			log << names[i] << ": " << tab[i]->getInputValue() << " ";
-		logAi->errorStream() << log.str();
+		logAi->error(log.str());
 		assert(false);
 	}
 
@@ -410,7 +410,7 @@ void FuzzyHelper::initVisitTile()
 	}
 	catch (fl::Exception & fe)
 	{
-		logAi->errorStream() << "visitTile " << ": " << fe.getWhat();
+		logAi->error("visitTile: %s",fe.getWhat());
 	}
 }
 
@@ -455,11 +455,10 @@ float FuzzyHelper::evaluate (Goals::VisitTile & g)
 	}
 	catch (fl::Exception & fe)
 	{
-		logAi->errorStream() << "evaluate VisitTile " << ": " << fe.getWhat();
+		logAi->error("evaluate VisitTile: %s",fe.getWhat());
 	}
 	assert (g.priority >= 0);
 	return g.priority;
-
 }
 float FuzzyHelper::evaluate (Goals::VisitHero & g)
 {
@@ -468,7 +467,7 @@ float FuzzyHelper::evaluate (Goals::VisitHero & g)
 		return -100; //hero died in the meantime
 	//TODO: consider direct copy (constructor?)
 	g.setpriority(Goals::VisitTile(obj->visitablePos()).sethero(g.hero).setisAbstract(g.isAbstract).accept(this));
-	return g.priority;	
+	return g.priority;
 }
 float FuzzyHelper::evaluate (Goals::GatherArmy & g)
 {
@@ -525,7 +524,7 @@ float FuzzyHelper::evaluate (Goals::Invalid & g)
 }
 float FuzzyHelper::evaluate (Goals::AbstractGoal & g)
 {
-	logAi->warnStream() << boost::format("Cannot evaluate goal %s") % g.name();
+	logAi->warn("Cannot evaluate goal %s", g.name());
 	return g.priority;
 }
 void FuzzyHelper::setPriority (Goals::TSubgoal & g)
diff --git a/AI/VCAI/Goals.cpp b/AI/VCAI/Goals.cpp
index b5f8d46c1..e798bfeee 100644
--- a/AI/VCAI/Goals.cpp
+++ b/AI/VCAI/Goals.cpp
@@ -182,7 +182,7 @@ namespace Goals
 
 //TSubgoal AbstractGoal::whatToDoToAchieve()
 //{
-//	logAi->debugStream() << boost::format("Decomposing goal of type %s") % name();
+//	logAi->debug("Decomposing goal of type %s",name());
 //	return sptr (Goals::Explore());
 //}
 
@@ -422,7 +422,7 @@ TSubgoal VisitHero::whatToDoToAchieve()
 	if (hero && ai->isAccessibleForHero(pos, hero, true) && isSafeToVisit(hero, pos)) //enemy heroes can get reinforcements
 	{
 		if (hero->pos == pos)
-			logAi->errorStream() << "Hero " << hero.name << " tries to visit himself.";
+			logAi->error("Hero %s tries to visit himself.", hero.name);
 		else
 		{
 			//can't use VISIT_TILE here as tile appears blocked by target hero
@@ -442,8 +442,7 @@ bool VisitHero::fulfillsMe (TSubgoal goal)
 	auto obj = cb->getObj(ObjectInstanceID(objid));
 	if (!obj)
 	{
-		logAi->errorStream() << boost::format("Hero %s: VisitHero::fulfillsMe at %s: object %d not found")
-			% hero.name % goal->tile % objid;
+		logAi->error("Hero %s: VisitHero::fulfillsMe at %s: object %d not found", hero.name, goal->tile, objid);
 		return false;
 	}
 	return obj->visitablePos() == goal->tile;
@@ -462,7 +461,7 @@ TSubgoal ClearWayTo::whatToDoToAchieve()
 	assert(cb->isInTheMap(tile)); //set tile
 	if(!cb->isVisible(tile))
 	{
-		logAi->errorStream() << "Clear way should be used with visible tiles!";
+		logAi->error("Clear way should be used with visible tiles!");
 		return sptr (Goals::Explore());
 	}
 
@@ -513,7 +512,7 @@ TGoalVec ClearWayTo::getAllPossibleSubgoals()
 
 			if (topObj->ID == Obj::HERO && cb->getPlayerRelations(h->tempOwner, topObj->tempOwner) != PlayerRelations::ENEMIES)
 				if (topObj != hero.get(true)) //the hero we want to free
-					logAi->errorStream() << boost::format("%s stands in the way of %s") % topObj->getObjectName()  % h->getObjectName();
+					logAi->error("%s stands in the way of %s", topObj->getObjectName(), h->getObjectName());
 			if (topObj->ID == Obj::QUEST_GUARD || topObj->ID == Obj::BORDERGUARD)
 			{
 				if (shouldVisit(h, topObj))
@@ -525,7 +524,7 @@ TGoalVec ClearWayTo::getAllPossibleSubgoals()
 				else
 				{
 					//TODO: we should be able to return apriopriate quest here (VCAI::striveToQuest)
-					logAi->debugStream() << "Quest guard blocks the way to " + tile();
+					logAi->debug("Quest guard blocks the way to %s", tile());
 					continue; //do not access quets guard if we can't complete the quest
 				}
 			}
@@ -545,7 +544,7 @@ TGoalVec ClearWayTo::getAllPossibleSubgoals()
 
 	if (ret.empty())
 	{
-		logAi->warnStream() << "There is no known way to clear the way to tile " + tile();
+		logAi->warn("There is no known way to clear the way to tile %s",tile());
 		throw goalFulfilledException (sptr(Goals::ClearWayTo(tile))); //make sure asigned hero gets unlocked
 	}
 
@@ -1129,7 +1128,7 @@ TGoalVec GatherArmy::getAllPossibleSubgoals()
 
 //TSubgoal AbstractGoal::whatToDoToAchieve()
 //{
-//	logAi->debugStream() << boost::format("Decomposing goal of type %s") % name();
+//	logAi->debug("Decomposing goal of type %s",name());
 //	return sptr (Goals::Explore());
 //}
 
diff --git a/AI/VCAI/VCAI.cpp b/AI/VCAI/VCAI.cpp
index 5edea5f1a..626b3fb8e 100644
--- a/AI/VCAI/VCAI.cpp
+++ b/AI/VCAI/VCAI.cpp
@@ -135,7 +135,7 @@ void VCAI::heroMoved(const TryMoveHero & details)
 				{
 					knownSubterraneanGates[o1] = o2;
 					knownSubterraneanGates[o2] = o1;
-					logAi->debugStream() << boost::format("Found a pair of subterranean gates between %s and %s!") % from % to;
+					logAi->debug("Found a pair of subterranean gates between %s and %s!", from(), to());
 				}
 			}
 		}