feat(master): outdated instances take nobody new and stop once empty

Instances on an old binary or old zone files are marked outdated: routing,
private passwords and merges skip them. Outdated properties remind their
players every 10 minutes that an update is waiting (ANNOUNCE) and stop once
empty. A new instance of the same property waits for the old one to be gone
before its world server starts, so two worlds never save one property.
The server list carries the flag after the endpoints (read when present).

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

dMasterServer/InstanceManager.h

@@ -1,9 +1,12 @@
 #pragma once
 
+#include <chrono>
 #include <functional>
 #include <algorithm>
+#include <optional>
 #include "SpareBackoff.h"
 #include <map>
+#include <set>
 #include <vector>
 #include "dCommonVars.h"
 #include "IServerOperations.h"
@@ -62,6 +65,17 @@ public:
 	// Its players are being moved to another instance (InstanceMigration.h): nobody new is sent here
 	bool GetIsDraining() const { return m_IsDraining; }
 	void SetIsDraining(bool value) { m_IsDraining = value; }
+	// Started before a live update, or on zone files that changed since: nobody new is sent here, and it stops once
+	// empty (OutdatedInstances.h)
+	bool GetIsOutdated() const { return m_IsOutdated; }
+	void SetIsOutdated(bool value) { m_IsOutdated = value; }
+	// A property instance waiting for the outdated instance of the same property to stop before its world server is
+	// started (so the two never both save it); requests for it wait as pending requests
+	bool GetIsWaitingForOld() const { return m_WaitingForOld; }
+	void SetIsWaitingForOld(bool value) { m_WaitingForOld = value; }
+	// When its players were last told an update is waiting (outdated properties)
+	std::optional<std::chrono::steady_clock::time_point> GetLastUpdateNotice() const { return m_LastUpdateNotice; }
+	void SetLastUpdateNotice(std::chrono::steady_clock::time_point value) { m_LastUpdateNotice = value; }
 	// Seats held for players being moved in; they count towards the caps until the move is over
 	int GetReserved() const { return m_Reserved; }
 	void SetReserved(int value) { m_Reserved = std::max(0, value); }
@@ -113,6 +127,7 @@ public:
 		view.isPrivate = GetIsPrivate();
 		view.shuttingDown = GetIsShuttingDown() || GetShutdownComplete();
 		view.draining = GetIsDraining();
+		view.outdated = GetIsOutdated();
 		return view;
 	}
 
@@ -129,6 +144,9 @@ private:
 	bool m_Ready{};
 	bool m_IsShuttingDown{};
 	bool m_IsDraining{};
+	bool m_IsOutdated{};
+	bool m_WaitingForOld{};
+	std::optional<std::chrono::steady_clock::time_point> m_LastUpdateNotice{};
 	int m_Reserved{};
 	std::vector<PendingInstanceRequest> m_PendingRequests{};
 	std::vector<PendingInstanceRequest> m_PendingAffirmations{};
@@ -192,6 +210,16 @@ public:
 	// Start an instance of each zone that has fewer instances with room than its spare_instances (one per call)
 	void KeepSpareInstances();
 
+	/**
+	 * Outdated instances (OutdatedInstances.h): reminds players on outdated properties that an update is waiting, and
+	 * stops outdated instances nobody is in or on the way to (not public instances of prestart_worlds zones: the live
+	 * update or reload replaces those). Called every frame; does its work once a second.
+	 */
+	void UpdateOutdatedInstances();
+
+	// Mark the running instances which() picks outdated (old binary or old zone files); returns how many were new
+	uint32_t MarkOutdated(const std::function<bool(const Instance&)>& which);
+
 private:
 	std::string mExternalIP;
 	std::vector<std::unique_ptr<Instance>> m_Instances;
@@ -210,5 +238,8 @@ private:
 	int GetSoftCap(LWOMAPID mapID);
 	int GetHardCap(LWOMAPID mapID);
 	const InstancePtr& CreateInstance(LWOMAPID mapID, LWOCLONEID cloneID);
+	// Start the world servers of property instances whose outdated predecessor is gone
+	void StartWaitingInstances();
 	std::function<void()> m_OnInstancesChanged;
+	std::chrono::steady_clock::time_point m_NextOutdatedCheck{};
 };