Index: binaries/data/mods/public/simulation/ai/common-api/entity.js
===================================================================
--- binaries/data/mods/public/simulation/ai/common-api/entity.js	(revision 21899)
+++ binaries/data/mods/public/simulation/ai/common-api/entity.js	(working copy)
@@ -335,7 +335,28 @@
 			return undefined;
 		return templates.replace(/\{native\}/g, this.civ()).replace(/\{civ\}/g, civ).split(/\s+/);
 	},
+	
+	"upgradableEntity": function(civ) {
+		// missing choices
+		let choices = this.get("Upgrade");
+		if (!choices)
+			return undefined;
 
+		return choices;
+	},
+	
+	"upgradeCost": function(civ) {
+		if (!this.get("Upgrade/Cost"))
+			return;
+
+		let ret = {};
+		for (let type in this.get("Upgrade/Cost/Resources"))
+			ret[type] = +this.get("Upgrade/Cost/Resources/" + type);
+		
+		warn(uneval(ret));
+		return ret;
+	},
+
 	"researchableTechs": function(gameState, civ) {
 		let templates = this.get("ProductionQueue/Technologies/_string");
 		if (!templates)
Index: binaries/data/mods/public/simulation/ai/petra/config.js
===================================================================
--- binaries/data/mods/public/simulation/ai/petra/config.js	(revision 21899)
+++ binaries/data/mods/public/simulation/ai/petra/config.js	(working copy)
@@ -89,6 +90,7 @@
 		"majorTech": 700,
 		"minorTech": 40,
 		"wonder": 1000,
+		"entityUpgrading": 80,
 		"emergency": 1000    // used only in emergency situations, should be the highest one
 	};
 
Index: binaries/data/mods/public/simulation/ai/petra/headquarters.js
===================================================================
--- binaries/data/mods/public/simulation/ai/petra/headquarters.js	(revision 21899)
+++ binaries/data/mods/public/simulation/ai/petra/headquarters.js	(working copy)
@@ -1891,6 +1891,31 @@
 		plan.queueToReset = "defenseBuilding";
 		queues.defenseBuilding.addPlan(plan);
 	}
+	
+	// Check for possible upgrades and do them if not saving resources
+	if (!this.saveResource)
+	{
+		let upgradableDefenses = gameState.getOwnEntitiesByClass("SentryTower", true).toEntityArray();
+		//warn(uneval(upgradableDefenses));
+
+		for (let ent of upgradableDefenses)
+		{
+			let upgradleEnt = ent.upgradableEntity();
+			let chosenUpgrade;
+			for (let choice of Object.keys(upgradableEnt))
+			{
+				// TODO Some fancy decision making
+				chosenUpgrade = choice;
+			}
+
+			let template = gameState.applyCiv(upgradableEnt[chosenUpgrade].Entity);
+			let plan = new m.UpgradePlan(gameState, ent, template);
+			let queue = "entityUpgrading";
+			plan.queueToReset = queue;
+			queues.entityUpgrading.addPlan(plan);
+			warn("added a queue");
+		}
+	}
 };
 
 m.HQ.prototype.buildBlacksmith = function(gameState, queues)
Index: binaries/data/mods/public/simulation/ai/petra/queueplanTraining.js
===================================================================
--- binaries/data/mods/public/simulation/ai/petra/queueplanTraining.js	(revision 21899)
+++ binaries/data/mods/public/simulation/ai/petra/queueplanTraining.js	(working copy)
@@ -1,7 +1,7 @@
 var PETRA = function(m)
 {
 
-m.TrainingPlan = function(gameState, type, metadata, number = 1, maxMerge = 5)
+m.TrainingPlan = function(gameState, type/*template_name*/, metadata, number = 1, maxMerge = 5)
 {
 	if (!m.QueuePlan.call(this, gameState, type, metadata))
 	{
Index: binaries/data/mods/public/simulation/ai/petra/queueplanUpgrading.js
===================================================================
--- binaries/data/mods/public/simulation/ai/petra/queueplanUpgrading.js	(nonexistent)
+++ binaries/data/mods/public/simulation/ai/petra/queueplanUpgrading.js	(working copy)
@@ -0,0 +1,67 @@
+var PETRA = function(m)
+{
+
+m.UpgradePlan = function(gameState, ent, template)
+{
+	this.entity = ent;
+	this.template = template;
+	this.cost = new API3.Resources(this.entity.upgradeCost());
+	this.category = "upgrading";
+	return true;
+};
+
+m.UpgradePlan.prototype = Object.create(m.QueuePlan.prototype);
+
+m.UpgradePlan.prototype.canStart = function(gameState)
+{
+	let needed = false;
+	/*if (this.entity.requiredTech() && !gameState.isResearched(this.entity.requiredTech()))
+		return false;*/
+	needed = true;
+	if (needed)
+		return true;
+};
+
+m.UpgradePlan.prototype.start = function(gameState)
+{
+	Engine.PostCommand(PlayerID, {
+		"type": "upgrade",
+		"entities": [this.entity.id()],
+		"template": this.template,
+		"queued": false
+	});
+
+	this.onStart(gameState);
+};
+
+m.UpgradePlan.prototype.getCost = function()
+{
+	return this.cost;
+};
+
+m.UpgradePlan.prototype.onStart = function(gameState)
+{
+	if (this.queueToReset)
+		gameState.ai.queueManager.changePriority(this.queueToReset, gameState.ai.Config.priorities[this.queueToReset]);
+};
+
+m.UpgradePlan.prototype.Serialize = function()
+{
+	return {
+		"entity": this.entity,
+		"cost": this.cost.Serialize(),
+		"queueToReset": this.queueToReset || undefined
+	};
+};
+
+m.UpgradePlan.prototype.Deserialize = function(gameState, data)
+{
+	for (let key in data)
+		this[key] = data[key];
+
+	this.cost = new API3.Resources();
+	this.cost.Deserialize(data.cost);
+};
+
+return m;
+}(PETRA);