Revert "Drop support for connecting to MT 0.4 servers" for our finalminetest

* This reverts commit f2ca6a6ca5e9dfe7bda3630a1ae41a94f7d02125.
* now all clients can connect to older servers or server

builtin/mainmenu/dlg_outdated_server.lua

@@ -0,0 +1,71 @@
+--MultiCraft
+--Copyright (C) 2022 MultiCraft Development Team
+--
+--This program is free software; you can redistribute it and/or modify
+--it under the terms of the GNU Lesser General Public License as published by
+--the Free Software Foundation; either version 3.0 of the License, or
+--(at your option) any later version.
+--
+--This program is distributed in the hope that it will be useful,
+--but WITHOUT ANY WARRANTY; without even the implied warranty of
+--MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+--GNU Lesser General Public License for more details.
+--
+--You should have received a copy of the GNU Lesser General Public License along
+--with this program; if not, write to the Free Software Foundation, Inc.,
+--51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
+
+local function outdated_server_formspec(this)
+	return ([[
+		style_type[image_button;content_offset=0]
+		image[4.9,0.3;2.5,2.5;%sattention.png]
+		style[msg;content_offset=0]
+		image_button[1,2.5;10,0.8;;msg;%s;false;false]
+		image_button[1,3.2;10,0.8;;msg;%s;false;false]
+		%s
+		button[2,4.5;4,0.8;cancel;%s]
+		%s
+		button[6,4.5;4,0.8;continue;%s]
+	]]):format(
+		defaulttexturedir_esc,
+		fgettext("The server you are trying to connect to is outdated!"),
+		fgettext("Support for older servers may be removed at any time."),
+		btn_style("cancel"),
+		fgettext("Cancel"),
+		btn_style("continue", "yellow"),
+		fgettext("Join anyway")
+	)
+end
+
+local function outdated_server_buttonhandler(this, fields)
+	if fields.cancel then
+		this:delete()
+		return true
+	end
+
+	if fields.continue then
+		serverlistmgr.add_favorite(this.server)
+
+		gamedata.servername = this.server.name
+		gamedata.serverdescription = this.server.description
+
+		core.settings:set_bool("auto_connect", false)
+		core.settings:set("connect_time", os.time())
+		core.settings:set("maintab_LAST", "online")
+		core.settings:set("address", gamedata.address)
+		core.settings:set("remote_port", gamedata.port)
+
+		core.start()
+	end
+end
+
+
+function create_outdated_server_dlg(server)
+	local retval = dialog_create("outdated_server_dlg",
+					outdated_server_formspec,
+					outdated_server_buttonhandler,
+					nil, true)
+	retval.server = server
+
+	return retval
+end

builtin/mainmenu/init.lua

@@ -47,6 +47,7 @@ dofile(menupath .. DIR_DELIM .. "dlg_create_world.lua")
 dofile(menupath .. DIR_DELIM .. "dlg_delete_content.lua")
 dofile(menupath .. DIR_DELIM .. "dlg_delete_world.lua")
 dofile(menupath .. DIR_DELIM .. "dlg_rename_modpack.lua")
+dofile(menupath .. DIR_DELIM .. "dlg_outdated_server.lua")
 
 if not mobile then
 	dofile(menupath .. DIR_DELIM .. "dlg_settings_advanced.lua")

builtin/mainmenu/tab_online.lua

@@ -165,6 +165,17 @@ local function get_formspec(tabview, name, tabdata)
 	return retval
 end
 
+local function is_favorite(server)
+	local favs = serverlistmgr.get_favorites()
+	for fav_id = 1, #favs do
+		if server.address == favs[fav_id].address and
+				server.port == favs[fav_id].port then
+			return true
+		end
+	end
+	return false
+end
+
 --------------------------------------------------------------------------------
 local function main_button_handler(tabview, fields, name, tabdata)
 	local serverlist = menudata.search_result or serverlistmgr.servers
@@ -374,6 +385,12 @@ local function main_button_handler(tabview, fields, name, tabdata)
 			if not is_server_protocol_compat_or_error(
 						fav.proto_min, fav.proto_max) then
 				return true
+			elseif fav.proto_max and fav.proto_max < 37 and not is_favorite(fav) then
+				local dlg = create_outdated_server_dlg(fav)
+				dlg:set_parent(tabview)
+				tabview:hide()
+				dlg:show()
+				return true
 			end
 
 			serverlistmgr.add_favorite(fav)

src/client/client.cpp

@@ -467,6 +467,10 @@ void Client::step(float dtime)
 			event->type = CE_PLAYER_DAMAGE;
 			event->player_damage.amount = damage;
 			m_client_event_queue.push(event);
+		} else if (envEvent.type == CEE_PLAYER_BREATH && m_proto_ver < 29) {
+			// Protocol v29 or greater obsoleted this event
+			u16 breath = envEvent.player_breath.amount;
+			sendBreath(breath);
 		}
 	}
 
@@ -850,6 +854,7 @@ void Client::ReceiveAll()
 
 inline void Client::handleCommand(NetworkPacket* pkt)
 {
+	pkt->setProtocolVersion(m_proto_ver);
 	const ToClientCommandHandler& opHandle = toClientCommandTable[pkt->getCommand()];
 	(this->*opHandle.handler)(pkt);
 }
@@ -968,7 +973,7 @@ void Client::interact(InteractAction action, const PointedThing& pointed)
 		[9 + plen] player position information
 	*/
 
-	NetworkPacket pkt(TOSERVER_INTERACT, 1 + 2 + 0);
+	NetworkPacket pkt(TOSERVER_INTERACT, 1 + 2 + 0, 0, m_proto_ver);
 
 	pkt << (u8)action;
 	pkt << myplayer->getWieldIndex();
@@ -1019,14 +1024,14 @@ AuthMechanism Client::choseAuthMech(const u32 mechs)
 
 void Client::sendInit(const std::string &playerName)
 {
-	NetworkPacket pkt(TOSERVER_INIT, 1 + 2 + 2 + (1 + playerName.size()) + 1);
+	NetworkPacket pkt(TOSERVER_INIT, 1 + 2 + 2 + (1 + playerName.size()));
 
 	// we don't support network compression yet
 	u16 supp_comp_modes = NETPROTO_COMPRESSION_NONE;
 
 	pkt << (u8) SER_FMT_VER_HIGHEST_READ << (u16) supp_comp_modes;
 	pkt << (u16) CLIENT_PROTOCOL_VERSION_MIN << (u16) CLIENT_PROTOCOL_VERSION_MAX;
-	pkt << playerName << (u8) 1;
+	pkt << playerName;
 
 	Send(&pkt);
 }
@@ -1263,8 +1268,27 @@ void Client::sendChangePassword(const std::string &oldpassword,
 
 void Client::sendDamage(u16 damage)
 {
-	NetworkPacket pkt(TOSERVER_DAMAGE, sizeof(u16));
+	// Minetest 0.4 uses uint8s instead of uint16s in TOSERVER_DAMAGE.
-	pkt << damage;
+	if (m_proto_ver >= 37) {
+		NetworkPacket pkt(TOSERVER_DAMAGE, sizeof(u16));
+		pkt << damage;
+		Send(&pkt);
+	} else {
+		u8 raw_damage = damage & 0xFF;
+		NetworkPacket pkt(TOSERVER_DAMAGE, sizeof(u8));
+		pkt << raw_damage;
+		Send(&pkt);
+	}
+}
+
+void Client::sendBreath(u16 breath)
+{
+	// Protocol v29 (Minetest 0.4.16) made this obsolete
+	if (m_proto_ver >= 29)
+		return;
+
+	NetworkPacket pkt(TOSERVER_BREATH, sizeof(u16));
+	pkt << breath;
 	Send(&pkt);
 }
 
@@ -1328,7 +1352,8 @@ void Client::sendPlayerPos()
 	player->last_camera_fov   = camera_fov;
 	player->last_wanted_range = wanted_range;
 
-	NetworkPacket pkt(TOSERVER_PLAYERPOS, 12 + 12 + 4 + 4 + 4 + 1 + 1);
+	NetworkPacket pkt(TOSERVER_PLAYERPOS, 12 + 12 + 4 + 4 + 4 + 1 + 1, 0,
+		m_proto_ver);
 
 	writePlayerPos(player, &map, &pkt);
 
@@ -1593,6 +1618,24 @@ void Client::typeChatMessage(const std::wstring &message)
 
 	// Send to others
 	sendChatMessage(message);
+
+	// Show locally
+	if (message[0] == L'/') {
+		if (!m_mods_loaded) {
+			ChatMessage *chatMessage = new ChatMessage(L"issued command: " +
+				message);
+			m_chat_queue.push(chatMessage);
+		}
+	} else if (m_proto_ver < 29) {
+		// Backwards compatibility
+		LocalPlayer *player = m_env.getLocalPlayer();
+		if (!player)
+			return;
+		std::wstring name = utf8_to_wide(player->getName());
+		ChatMessage *chatMessage = new ChatMessage(CHATMESSAGE_TYPE_NORMAL,
+			message, name);
+		m_chat_queue.push(chatMessage);
+	}
 }
 
 void Client::addUpdateMeshTask(v3s16 p, bool ack_to_server, bool urgent)

src/client/client.h

@@ -179,6 +179,7 @@ public:
 	void handleCommand_BlockData(NetworkPacket* pkt);
 	void handleCommand_Inventory(NetworkPacket* pkt);
 	void handleCommand_TimeOfDay(NetworkPacket* pkt);
+	void handleCommand_ChatMessageOld(NetworkPacket *pkt);
 	void handleCommand_ChatMessage(NetworkPacket *pkt);
 	void handleCommand_ActiveObjectRemoveAdd(NetworkPacket* pkt);
 	void handleCommand_ActiveObjectMessages(NetworkPacket* pkt);
@@ -241,6 +242,7 @@ public:
 	void sendChangePassword(const std::string &oldpassword,
 		const std::string &newpassword, const bool close_form = false);
 	void sendDamage(u16 damage);
+	void sendBreath(u16 breath);
 	void sendRespawn();
 	void sendReady();
 

src/client/clientenvironment.cpp

@@ -271,6 +271,75 @@ void ClientEnvironment::step(float dtime)
 	if (m_client->modsLoaded())
 		m_script->environment_step(dtime);
 
+	// Protocol v29 make this behaviour obsolete
+	if (getGameDef()->getProtoVersion() < 29) {
+		if (m_lava_hurt_interval.step(dtime, 1.0)) {
+			v3f pf = lplayer->getPosition();
+
+			// Feet, middle and head
+			v3s16 p1 = floatToInt(pf + v3f(0, BS * 0.1, 0), BS);
+			MapNode n1 = m_map->getNode(p1);
+			v3s16 p2 = floatToInt(pf + v3f(0, BS * 0.8, 0), BS);
+			MapNode n2 = m_map->getNode(p2);
+			v3s16 p3 = floatToInt(pf + v3f(0, BS * 1.6, 0), BS);
+			MapNode n3 = m_map->getNode(p3);
+
+			u32 damage_per_second = 0;
+			damage_per_second = MYMAX(damage_per_second,
+				m_client->ndef()->get(n1).damage_per_second);
+			damage_per_second = MYMAX(damage_per_second,
+				m_client->ndef()->get(n2).damage_per_second);
+			damage_per_second = MYMAX(damage_per_second,
+				m_client->ndef()->get(n3).damage_per_second);
+
+			if (damage_per_second != 0)
+				damageLocalPlayer(damage_per_second, true);
+		}
+
+		/*
+			Drowning
+		*/
+		if (m_drowning_interval.step(dtime, 2.0)) {
+			v3f pf = lplayer->getPosition();
+
+			// head
+			v3s16 p = floatToInt(pf + v3f(0, BS * 1.6, 0), BS);
+			MapNode n = m_map->getNode(p);
+			const ContentFeatures &c = m_client->ndef()->get(n);
+			u8 drowning_damage = c.drowning;
+			if (drowning_damage > 0 && lplayer->hp > 0) {
+				u16 breath = lplayer->getBreath();
+				if (breath > 10)
+					breath = 11;
+				if (breath > 0)
+					breath -= 1;
+				lplayer->setBreath(breath);
+				updateLocalPlayerBreath(breath);
+			}
+
+			if (lplayer->getBreath() == 0 && drowning_damage > 0)
+				damageLocalPlayer(drowning_damage, true);
+		}
+		if (m_breathing_interval.step(dtime, 0.5)) {
+			v3f pf = lplayer->getPosition();
+
+			// head
+			v3s16 p = floatToInt(pf + v3f(0, BS * 1.6, 0), BS);
+			MapNode n = m_map->getNode(p);
+			const ContentFeatures &c = m_client->ndef()->get(n);
+			if (!lplayer->hp) {
+				lplayer->setBreath(11);
+			} else if (c.drowning == 0) {
+				u16 breath = lplayer->getBreath();
+				if (breath <= 10) {
+					breath += 1;
+					lplayer->setBreath(breath);
+					updateLocalPlayerBreath(breath);
+				}
+			}
+		}
+	}
+
 	// Update lighting on local player (used for wield item)
 	u32 day_night_ratio = getDayNightRatio();
 	{
@@ -449,6 +518,14 @@ void ClientEnvironment::damageLocalPlayer(u16 damage, bool handle_hp)
 	m_client_event_queue.push(event);
 }
 
+void ClientEnvironment::updateLocalPlayerBreath(u16 breath)
+{
+	ClientEnvEvent event;
+	event.type = CEE_PLAYER_BREATH;
+	event.player_breath.amount = breath;
+	m_client_event_queue.push(event);
+}
+
 /*
 	Client likes to call these
 */

src/client/clientenvironment.h

@@ -43,7 +43,8 @@ class LocalPlayer;
 enum ClientEnvEventType
 {
 	CEE_NONE,
-	CEE_PLAYER_DAMAGE
+	CEE_PLAYER_DAMAGE,
+	CEE_PLAYER_BREATH
 };
 
 struct ClientEnvEvent
@@ -56,6 +57,9 @@ struct ClientEnvEvent
 			u16 amount;
 			bool send_to_server;
 		} player_damage;
+		struct{
+			u16 amount;
+		} player_breath;
 	};
 };
 
@@ -113,6 +117,7 @@ public:
 	*/
 
 	void damageLocalPlayer(u16 damage, bool handle_hp=true);
+	void updateLocalPlayerBreath(u16 breath);
 
 	/*
 		Client likes to call these
@@ -151,6 +156,9 @@ private:
 	std::vector<ClientSimpleObject*> m_simple_objects;
 	std::queue<ClientEnvEvent> m_client_event_queue;
 	IntervalLimiter m_active_object_light_update_interval;
+	IntervalLimiter m_lava_hurt_interval;
+	IntervalLimiter m_drowning_interval;
+	IntervalLimiter m_breathing_interval;
 	std::list<std::string> m_player_names;
 	v3s16 m_camera_offset;
 };

src/client/content_cao.cpp

@@ -357,6 +357,8 @@ void GenericCAO::initialize(const std::string &data)
 
 			m_prop.show_on_minimap = false;
 		}
+		if (m_client->getProtoVersion() < 33)
+			m_env->addPlayerName(m_name.c_str());
 	}
 
 	m_enable_shaders = g_settings->getBool("enable_shaders");
@@ -365,21 +367,25 @@ void GenericCAO::initialize(const std::string &data)
 void GenericCAO::processInitData(const std::string &data)
 {
 	std::istringstream is(data, std::ios::binary);
+
 	const u8 version = readU8(is);
+	const u16 protocol_version = m_client->getProtoVersion();
 
-	if (version < 1) {
+	// PROTOCOL_VERSION >= 14
-		errorstream << "GenericCAO: Unsupported init data version"
-				<< std::endl;
-		return;
-	}
-
-	// PROTOCOL_VERSION >= 37
 	m_name = deSerializeString16(is);
 	m_is_player = readU8(is);
-	m_id = readU16(is);
+	if (protocol_version >= 37) {
-	m_position = readV3F32(is);
+		m_id = readU16(is);
-	m_rotation = readV3F32(is);
+		m_position = readV3F32(is);
-	m_hp = readU16(is);
+		m_rotation = readV3F32(is);
+		m_hp = readU16(is);
+	} else {
+		if (version >= 1)
+			m_id = readS16(is);
+		m_position = readV3F1000(is);
+		m_rotation = v3f(0.0, readF1000(is), 0.0);
+		m_hp = readS16(is);
+	}
 
 	const u8 num_messages = readU8(is);
 
@@ -396,6 +402,8 @@ void GenericCAO::processInitData(const std::string &data)
 
 GenericCAO::~GenericCAO()
 {
+	if (m_is_player && m_client->getProtoVersion() < 33)
+		m_env->removePlayerName(m_name.c_str());
 	removeFromScene(true);
 }
 
@@ -675,8 +683,9 @@ void GenericCAO::addToScene(ITextureSource *tsrc)
 				video::S3DVertex( dx,  dy, 0, 0,0,1, c, 0,0),
 				video::S3DVertex(-dx,  dy, 0, 0,0,1, c, 1,0),
 			};
-			if (m_is_player) {
+			if (m_is_player && m_client->getProtoVersion() >= 36) {
 				// Move minimal Y position to 0 (feet position)
+				// This should not be done on Minetest 0.4 servers
 				for (video::S3DVertex &vertex : vertices)
 					vertex.Pos.Y += dy;
 			}
@@ -706,8 +715,9 @@ void GenericCAO::addToScene(ITextureSource *tsrc)
 				video::S3DVertex(-dx, dy, 0, 0,0,-1, c, 0,0),
 				video::S3DVertex( dx, dy, 0, 0,0,-1, c, 1,0),
 			};
-			if (m_is_player) {
+			if (m_is_player && m_client->getProtoVersion() >= 36) {
 				// Move minimal Y position to 0 (feet position)
+				// This should not be done on Minetest 0.4 servers
 				for (video::S3DVertex &vertex : vertices)
 					vertex.Pos.Y += dy;
 			}
@@ -776,7 +786,7 @@ void GenericCAO::addToScene(ITextureSource *tsrc)
 			setSceneNodeMaterial(m_animated_meshnode);
 
 			m_animated_meshnode->setMaterialFlag(video::EMF_BACK_FACE_CULLING,
-				m_prop.backface_culling);
+				!m_is_player && m_prop.backface_culling);
 		} else
 			errorstream<<"GenericCAO::addToScene(): Could not load mesh "<<m_prop.mesh<<std::endl;
 	} else if (m_prop.visual == "wielditem" || m_prop.visual == "item") {
@@ -987,6 +997,8 @@ void GenericCAO::step(float dtime, ClientEnvironment *env)
 	if (m_is_local_player) {
 		LocalPlayer *player = m_env->getLocalPlayer();
 		m_position = player->getPosition();
+		if (m_client->getProtoVersion() < 36)
+			m_position += v3f(0,BS,0);
 		pos_translator.val_current = m_position;
 		m_rotation.Y = wrapDegrees_0_360(player->getYaw());
 		rot_translator.val_current = m_rotation;
@@ -1626,6 +1638,7 @@ void GenericCAO::processMessage(const std::string &data)
 	std::istringstream is(data, std::ios::binary);
 	// command
 	u8 cmd = readU8(is);
+	const u16 protocol_version = m_client->getProtoVersion();
 	if (cmd == AO_CMD_SET_PROPERTIES) {
 		ObjectProperties newprops;
 		newprops.show_on_minimap = m_is_player; // default
@@ -1653,10 +1666,14 @@ void GenericCAO::processMessage(const std::string &data)
 		if (m_is_local_player) {
 			LocalPlayer *player = m_env->getLocalPlayer();
 			player->makes_footstep_sound = m_prop.makes_footstep_sound;
-			aabb3f collision_box = m_prop.collisionbox;
+			// Only set the collision box on Minetest 5.0.0+ to ensure
-			collision_box.MinEdge *= BS;
+			// compatibility with 0.4.
-			collision_box.MaxEdge *= BS;
+			if (protocol_version >= 36) {
-			player->setCollisionbox(collision_box);
+				aabb3f collision_box = m_prop.collisionbox;
+				collision_box.MinEdge *= BS;
+				collision_box.MaxEdge *= BS;
+				player->setCollisionbox(collision_box);
+			}
 			player->setEyeHeight(m_prop.eye_height);
 			player->setZoomFOV(m_prop.zoom_fov);
 		}
@@ -1682,15 +1699,19 @@ void GenericCAO::processMessage(const std::string &data)
 	} else if (cmd == AO_CMD_UPDATE_POSITION) {
 		// Not sent by the server if this object is an attachment.
 		// We might however get here if the server notices the object being detached before the client.
-		m_position = readV3F32(is);
+		m_position = readV3F(is, protocol_version);
-		m_velocity = readV3F32(is);
+		m_velocity = readV3F(is, protocol_version);
-		m_acceleration = readV3F32(is);
+		m_acceleration = readV3F(is, protocol_version);
-		m_rotation = readV3F32(is);
+		if (protocol_version >= 37)
+			m_rotation = readV3F32(is);
+		else
+			m_rotation = v3f(0.0, readF1000(is), 0.0);
+
 
 		m_rotation = wrapDegrees_0_360_v3f(m_rotation);
 		bool do_interpolate = readU8(is);
 		bool is_end_position = readU8(is);
-		float update_interval = readF32(is);
+		float update_interval = readF(is, protocol_version);
 
 		// Place us a bit higher if we're physical, to not sink into
 		// the ground due to sucky collision detection...
@@ -1721,7 +1742,7 @@ void GenericCAO::processMessage(const std::string &data)
 	} else if (cmd == AO_CMD_SET_SPRITE) {
 		v2s16 p = readV2S16(is);
 		int num_frames = readU16(is);
-		float framelength = readF32(is);
+		float framelength = readF(is, protocol_version);
 		bool select_horiz_by_yawpitch = readU8(is);
 
 		m_tx_basepos = p;
@@ -1731,9 +1752,9 @@ void GenericCAO::processMessage(const std::string &data)
 
 		updateTexturePos();
 	} else if (cmd == AO_CMD_SET_PHYSICS_OVERRIDE) {
-		float override_speed = readF32(is);
+		float override_speed = readF(is, protocol_version);
-		float override_jump = readF32(is);
+		float override_jump = readF(is, protocol_version);
-		float override_gravity = readF32(is);
+		float override_gravity = readF(is, protocol_version);
 		// these are sent inverted so we get true when the server sends nothing
 		bool sneak = !readU8(is);
 		bool sneak_glitch = !readU8(is);
@@ -1752,11 +1773,11 @@ void GenericCAO::processMessage(const std::string &data)
 		}
 	} else if (cmd == AO_CMD_SET_ANIMATION) {
 		// TODO: change frames send as v2s32 value
-		v2f range = readV2F32(is);
+		v2f range = readV2F(is, protocol_version);
 		if (!m_is_local_player) {
 			m_animation_range = v2s32((s32)range.X, (s32)range.Y);
-			m_animation_speed = readF32(is);
+			m_animation_speed = readF(is, protocol_version);
-			m_animation_blend = readF32(is);
+			m_animation_blend = readF(is, protocol_version);
 			// these are sent inverted so we get true when the server sends nothing
 			m_animation_loop = !readU8(is);
 			updateAnimation();
@@ -1765,8 +1786,8 @@ void GenericCAO::processMessage(const std::string &data)
 			if(player->last_animation == NO_ANIM)
 			{
 				m_animation_range = v2s32((s32)range.X, (s32)range.Y);
-				m_animation_speed = readF32(is);
+				m_animation_speed = readF(is, protocol_version);
-				m_animation_blend = readF32(is);
+				m_animation_blend = readF(is, protocol_version);
 				// these are sent inverted so we get true when the server sends nothing
 				m_animation_loop = !readU8(is);
 			}
@@ -1785,25 +1806,30 @@ void GenericCAO::processMessage(const std::string &data)
 			}
 		}
 	} else if (cmd == AO_CMD_SET_ANIMATION_SPEED) {
-		m_animation_speed = readF32(is);
+		m_animation_speed = readF(is, protocol_version);
 		updateAnimationSpeed();
 	} else if (cmd == AO_CMD_SET_BONE_POSITION) {
 		std::string bone = deSerializeString16(is);
-		v3f position = readV3F32(is);
+		v3f position = readV3F(is, protocol_version);
-		v3f rotation = readV3F32(is);
+		v3f rotation = readV3F(is, protocol_version);
 		m_bone_position[bone] = core::vector2d<v3f>(position, rotation);
 
 		// updateBonePosition(); now called every step
 	} else if (cmd == AO_CMD_ATTACH_TO) {
 		u16 parent_id = readS16(is);
 		std::string bone = deSerializeString16(is);
-		v3f position = readV3F32(is);
+		v3f position = readV3F(is, protocol_version);
-		v3f rotation = readV3F32(is);
+		v3f rotation = readV3F(is, protocol_version);
 		bool force_visible = readU8(is); // Returns false for EOF
 
 		setAttachment(parent_id, bone, position, rotation, force_visible);
 	} else if (cmd == AO_CMD_PUNCHED) {
 		u16 result_hp = readU16(is);
+		if (protocol_version < 37) {
+			// This is not a bug, the above readU16() is intentionally executed
+			// on older protocols as there used to be a damage value sent.
+			result_hp = readS16(is);
+		}
 
 		// Use this instead of the send damage to not interfere with prediction
 		s32 damage = (s32)m_hp - (s32)result_hp;

src/client/game.cpp

@@ -2648,6 +2648,11 @@ void Game::handleClientEvent_None(ClientEvent *event, CameraOrientation *cam)
 
 void Game::handleClientEvent_PlayerDamage(ClientEvent *event, CameraOrientation *cam)
 {
+	// Don't do anything if proto_ver < 36 and the player is dead.
+	// This reverts the change introduced in dcd1a15 for old servers.
+	if (client->getProtoVersion() < 36 && client->getHP() == 0)
+		return;
+
 	if (client->modsLoaded())
 		client->getScript()->on_damage_taken(event->player_damage.amount);
 

src/client/localplayer.cpp

@@ -743,6 +743,14 @@ ClientActiveObject *LocalPlayer::getParent() const
 	return m_cao ? m_cao->getParent() : nullptr;
 }
 
+float LocalPlayer::getZoomFOV() const
+{
+	// OH nO, The ZOOm FoV IS nOt COnFIguRABLE On oLDER ServErS.
+	if (m_client && m_client->getProtoVersion() < 36)
+		return m_client->checkPrivilege("zoom") ? 15.0f : 0.0f;
+	return m_zoom_fov;
+}
+
 bool LocalPlayer::isDead() const
 {
 	FATAL_ERROR_IF(!getCAO(), "LocalPlayer's CAO isn't initialized");

src/client/localplayer.h

@@ -146,7 +146,7 @@ public:
 
 	const aabb3f& getCollisionbox() const { return m_collisionbox; }
 
-	float getZoomFOV() const { return m_zoom_fov; }
+	float getZoomFOV() const;
 	void setZoomFOV(float zoom_fov) { m_zoom_fov = zoom_fov; }
 
 	bool getAutojump() const { return m_autojump; }

src/itemdef.cpp

@@ -192,7 +192,7 @@ void ItemDefinition::deSerialize(std::istream &is)
 
 	// Deserialize
 	int version = readU8(is);
-	if (version < 6)
+	if (version < 1 || (version > 3 && version < 6))
 		throw SerializationError("unsupported ItemDefinition version");
 
 	type = (enum ItemType)readU8(is);
@@ -200,7 +200,10 @@ void ItemDefinition::deSerialize(std::istream &is)
 	description = deSerializeString16(is);
 	inventory_image = deSerializeString16(is);
 	wield_image = deSerializeString16(is);
-	wield_scale = readV3F32(is);
+	if (version >= 6)
+		wield_scale = readV3F32(is);
+	else
+		wield_scale = readV3F1000(is);
 	stack_max = readS16(is);
 	usable = readU8(is);
 	liquids_pointable = readU8(is);
@@ -220,21 +223,37 @@ void ItemDefinition::deSerialize(std::istream &is)
 		groups[name] = value;
 	}
 
+	if (version < 2) {
+		// We can't be sure that node_placement_prediction is sent in version 1.
+		try {
+			node_placement_prediction = deSerializeString16(is);
+		} catch (SerializationError &e) {};
+		sound_place.name = "default_place_node";
+		sound_place.gain = 0.5;
+		return;
+	}
+
 	node_placement_prediction = deSerializeString16(is);
 
 	// Version from ContentFeatures::serialize to keep in sync
-	sound_place.deSerialize(is, CONTENTFEATURES_VERSION);
+	const u8 cf_version = version >= 6 ? CONTENTFEATURES_VERSION : 9;
-	sound_place_failed.deSerialize(is, CONTENTFEATURES_VERSION);
+	sound_place.deSerialize(is, cf_version);
-
-	range = readF32(is);
-	palette_image = deSerializeString16(is);
-	color = readARGB8(is);
-	inventory_overlay = deSerializeString16(is);
-	wield_overlay = deSerializeString16(is);
 
 	// If you add anything here, insert it primarily inside the try-catch
 	// block to not need to increase the version.
 	try {
+		if (version >= 6) {
+			sound_place_failed.deSerialize(is, cf_version);
+			range = readF32(is);
+		} else {
+			if (version >= 3)
+				range = readF1000(is);
+			sound_place_failed.deSerialize(is, cf_version);
+		}
+		palette_image = deSerializeString16(is);
+		color = readARGB8(is);
+		inventory_overlay = deSerializeString16(is);
+		wield_overlay = deSerializeString16(is);
 		short_description = deSerializeString16(is);
 	} catch(SerializationError &e) {};
 }

src/network/clientopcodes.cpp

@@ -72,7 +72,7 @@ const ToClientCommandHandler toClientCommandTable[TOCLIENT_NUM_MSG_TYPES] =
 	null_command_handler,
 	null_command_handler,
 	{ "TOCLIENT_CHAT_MESSAGE",             TOCLIENT_STATE_CONNECTED, &Client::handleCommand_ChatMessage }, // 0x2F
-	null_command_handler, // 0x30
+	{ "TOCLIENT_CHAT_MESSAGE_OLD",         TOCLIENT_STATE_CONNECTED, &Client::handleCommand_ChatMessageOld }, // 0x30
 	{ "TOCLIENT_ACTIVE_OBJECT_REMOVE_ADD", TOCLIENT_STATE_CONNECTED, &Client::handleCommand_ActiveObjectRemoveAdd }, // 0x31
 	{ "TOCLIENT_ACTIVE_OBJECT_MESSAGES",   TOCLIENT_STATE_CONNECTED, &Client::handleCommand_ActiveObjectMessages }, // 0x32
 	{ "TOCLIENT_HP",                       TOCLIENT_STATE_CONNECTED, &Client::handleCommand_HP }, // 0x33

src/network/clientpackethandler.cpp

@@ -397,6 +397,35 @@ void Client::handleCommand_TimeOfDay(NetworkPacket* pkt)
 	//		<< " dr=" << dr << std::endl;
 }
 
+void Client::handleCommand_ChatMessageOld(NetworkPacket* pkt)
+{
+	/*
+		u16 command
+		u16 length
+		wstring message
+	*/
+	u16 len, read_wchar;
+
+	*pkt >> len;
+
+	std::wstring message;
+	for (u32 i = 0; i < len; i++) {
+		*pkt >> read_wchar;
+		message += (wchar_t)read_wchar;
+	}
+
+	ChatMessage *chatMessage = new ChatMessage(message);
+
+	// @TODO send this to CSM using ChatMessage object
+	if (modsLoaded() && m_script->on_receiving_message(
+			wide_to_utf8(chatMessage->message))) {
+		// Message was consumed by CSM and should not be handled by client
+		delete chatMessage;
+	} else {
+		pushToChatQueue(chatMessage);
+	}
+}
+
 void Client::handleCommand_ChatMessage(NetworkPacket *pkt)
 {
 	/*
@@ -560,7 +589,13 @@ void Client::handleCommand_HP(NetworkPacket *pkt)
 	u16 oldhp = player->hp;
 
 	u16 hp;
-	*pkt >> hp;
+	if (m_proto_ver >= 37) {
+		*pkt >> hp;
+	} else {
+		u8 raw_hp;
+		*pkt >> raw_hp;
+		hp = raw_hp;
+	}
 
 	player->hp = hp;
 
@@ -916,6 +951,27 @@ void Client::handleCommand_InventoryFormSpec(NetworkPacket* pkt)
 
 void Client::handleCommand_DetachedInventory(NetworkPacket* pkt)
 {
+	// TODO: Unify this legacy code with the new code.
+	if (m_proto_ver < 37) {
+		std::string datastring(pkt->getString(0), pkt->getSize());
+		std::istringstream is(datastring, std::ios_base::binary);
+
+		std::string name = deSerializeString16(is);
+
+		infostream << "Client: Detached inventory update: \"" << name
+				<< "\"" << std::endl;
+
+		Inventory *inv = nullptr;
+		if (m_detached_inventories.count(name) > 0)
+			inv = m_detached_inventories[name];
+		else {
+			inv = new Inventory(m_itemdef);
+			m_detached_inventories[name] = inv;
+		}
+		inv->deSerialize(is);
+		return;
+	}
+
 	std::string name;
 	bool keep_inv = true;
 	*pkt >> name >> keep_inv;
@@ -988,17 +1044,17 @@ void Client::handleCommand_AddParticleSpawner(NetworkPacket* pkt)
 	u16 attached_id = 0;
 
 	p.amount             = readU16(is);
-	p.time               = readF32(is);
+	p.time               = readF(is, m_proto_ver);
-	p.minpos             = readV3F32(is);
+	p.minpos             = readV3F(is, m_proto_ver);
-	p.maxpos             = readV3F32(is);
+	p.maxpos             = readV3F(is, m_proto_ver);
-	p.minvel             = readV3F32(is);
+	p.minvel             = readV3F(is, m_proto_ver);
-	p.maxvel             = readV3F32(is);
+	p.maxvel             = readV3F(is, m_proto_ver);
-	p.minacc             = readV3F32(is);
+	p.minacc             = readV3F(is, m_proto_ver);
-	p.maxacc             = readV3F32(is);
+	p.maxacc             = readV3F(is, m_proto_ver);
-	p.minexptime         = readF32(is);
+	p.minexptime         = readF(is, m_proto_ver);
-	p.maxexptime         = readF32(is);
+	p.maxexptime         = readF(is, m_proto_ver);
-	p.minsize            = readF32(is);
+	p.minsize            = readF(is, m_proto_ver);
-	p.maxsize            = readF32(is);
+	p.maxsize            = readF(is, m_proto_ver);
 	p.collisiondetection = readU8(is);
 	p.texture            = deSerializeString32(is);
 
@@ -1009,7 +1065,7 @@ void Client::handleCommand_AddParticleSpawner(NetworkPacket* pkt)
 
 	attached_id = readU16(is);
 
-	p.animation.deSerialize(is, m_proto_ver);
+	p.animation.deSerializeWithProtoVer(is, m_proto_ver);
 	p.glow = readU8(is);
 	p.object_collision = readU8(is);
 

src/network/connection.h

@@ -177,6 +177,7 @@ controltype and data description:
 #define CONTROLTYPE_SET_PEER_ID 1
 #define CONTROLTYPE_PING 2
 #define CONTROLTYPE_DISCO 3
+#define CONTROLTYPE_ENABLE_BIG_SEND_WINDOW 4
 
 /*
 ORIGINAL: This is a plain packet with no control and no error
@@ -313,7 +314,8 @@ enum ConnectionCommandType{
 	CONNCMD_SEND,
 	CONNCMD_SEND_TO_ALL,
 	CONCMD_ACK,
-	CONCMD_CREATE_PEER
+	CONCMD_CREATE_PEER,
+	CONCMD_DISABLE_LEGACY
 };
 
 struct ConnectionCommand
@@ -368,6 +370,16 @@ struct ConnectionCommand
 		reliable = true;
 		raw = true;
 	}
+
+	void disableLegacy(session_t peer_id_, const SharedBuffer<u8> &data_)
+	{
+		type = CONCMD_DISABLE_LEGACY;
+		peer_id = peer_id_;
+		data = data_;
+		channelnum = 0;
+		reliable = true;
+		raw = true;
+	}
 };
 
 /* maximum window size to use, 0xFFFF is theoretical maximum. don't think about

src/network/connectionthreads.cpp

@@ -405,6 +405,15 @@ void ConnectionSendThread::processReliableCommand(ConnectionCommand &c)
 			}
 			return;
 
+		case CONCMD_DISABLE_LEGACY:
+			LOG(dout_con << m_connection->getDesc()
+				<< "UDP processing reliable CONCMD_DISABLE_LEGACY" << std::endl);
+			if (!rawSendAsPacket(c.peer_id, c.channelnum, c.data, c.reliable)) {
+				/* put to queue if we couldn't send it immediately */
+				sendReliable(c);
+			}
+			return;
+
 		case CONNCMD_SERVE:
 		case CONNCMD_CONNECT:
 		case CONNCMD_DISCONNECT:
@@ -1185,6 +1194,17 @@ SharedBuffer<u8> ConnectionReceiveThread::handlePacketType_Control(Channel *chan
 			m_connection->SetPeerID(peer_id_new);
 		}
 
+		// Request the server disables "legacy peer mode" (0.4.X servers
+		// throttle outgoing packets if this does not happen).
+		// Minetest 5.X servers *should* ignore this.
+		ConnectionCommand cmd;
+
+		SharedBuffer<u8> reply(2);
+		writeU8(&reply[0], PACKET_TYPE_CONTROL);
+		writeU8(&reply[1], CONTROLTYPE_ENABLE_BIG_SEND_WINDOW);
+		cmd.disableLegacy(PEER_ID_SERVER, reply);
+		m_connection->putCommand(cmd);
+
 		throw ProcessedSilentlyException("Got a SET_PEER_ID");
 	} else if (controltype == CONTROLTYPE_PING) {
 		// Just ignore it, the incoming data already reset

src/network/networkprotocol.h

@@ -218,7 +218,7 @@ with this program; if not, write to the Free Software Foundation, Inc.,
 // Client's supported network protocol range
 // The minimal version depends on whether
 // send_pre_v25_init is enabled or not
-#define CLIENT_PROTOCOL_VERSION_MIN 37
+#define CLIENT_PROTOCOL_VERSION_MIN 25
 #define CLIENT_PROTOCOL_VERSION_MAX LATEST_PROTOCOL_VERSION
 
 // Constant that differentiates the protocol from random data and other protocols

src/nodedef.cpp

@@ -152,32 +152,34 @@ void NodeBox::serialize(std::ostream &os, u16 protocol_version) const
 void NodeBox::deSerialize(std::istream &is)
 {
 	int version = readU8(is);
-	if (version < 6)
+	if (version < 1 || (version > 3 && version < 6))
 		throw SerializationError("unsupported NodeBox version");
 
 	reset();
 
 	type = (enum NodeBoxType)readU8(is);
 
+	// An approximate protocol version.
+	const u16 protocol_version = version > 3 ? 37 : 32;
 	if(type == NODEBOX_FIXED || type == NODEBOX_LEVELED)
 	{
 		u16 fixed_count = readU16(is);
 		while(fixed_count--)
 		{
 			aabb3f box;
-			box.MinEdge = readV3F32(is);
+			box.MinEdge = readV3F(is, protocol_version);
-			box.MaxEdge = readV3F32(is);
+			box.MaxEdge = readV3F(is, protocol_version);
 			fixed.push_back(box);
 		}
 	}
 	else if(type == NODEBOX_WALLMOUNTED)
 	{
-		wall_top.MinEdge = readV3F32(is);
+		wall_top.MinEdge = readV3F(is, protocol_version);
-		wall_top.MaxEdge = readV3F32(is);
+		wall_top.MaxEdge = readV3F(is, protocol_version);
-		wall_bottom.MinEdge = readV3F32(is);
+		wall_bottom.MinEdge = readV3F(is, protocol_version);
-		wall_bottom.MaxEdge = readV3F32(is);
+		wall_bottom.MaxEdge = readV3F(is, protocol_version);
-		wall_side.MinEdge = readV3F32(is);
+		wall_side.MinEdge = readV3F(is, protocol_version);
-		wall_side.MaxEdge = readV3F32(is);
+		wall_side.MaxEdge = readV3F(is, protocol_version);
 	}
 	else if (type == NODEBOX_CONNECTED)
 	{
@@ -185,8 +187,8 @@ void NodeBox::deSerialize(std::istream &is)
 		count = readU16(is); \
 		(box).reserve(count); \
 		while (count--) { \
-			v3f min = readV3F32(is); \
+			v3f min = readV3F(is, protocol_version); \
-			v3f max = readV3F32(is); \
+			v3f max = readV3F(is, protocol_version); \
 			(box).emplace_back(min, max); }; }
 
 		u16 count;
@@ -198,6 +200,8 @@ void NodeBox::deSerialize(std::istream &is)
 		READBOXES(connect_left);
 		READBOXES(connect_back);
 		READBOXES(connect_right);
+		if (version <= 3)
+			return;
 		READBOXES(disconnected_top);
 		READBOXES(disconnected_bottom);
 		READBOXES(disconnected_front);
@@ -287,17 +291,37 @@ void TileDef::deSerialize(std::istream &is, u8 contentfeatures_version,
 	NodeDrawType drawtype)
 {
 	int version = readU8(is);
-	if (version < 6)
-		throw SerializationError("unsupported TileDef version");
 	name = deSerializeString16(is);
 	animation.deSerialize(is, version);
-	u16 flags = readU16(is);
+
-	backface_culling = flags & TILE_FLAG_BACKFACE_CULLING;
+	bool has_scale = false;
-	tileable_horizontal = flags & TILE_FLAG_TILEABLE_HORIZONTAL;
+	bool has_align_style = false;
-	tileable_vertical = flags & TILE_FLAG_TILEABLE_VERTICAL;
+	if (version >= 6) {
-	has_color = flags & TILE_FLAG_HAS_COLOR;
+		u16 flags = readU16(is);
-	bool has_scale = flags & TILE_FLAG_HAS_SCALE;
+		backface_culling = flags & TILE_FLAG_BACKFACE_CULLING;
-	bool has_align_style = flags & TILE_FLAG_HAS_ALIGN_STYLE;
+		tileable_horizontal = flags & TILE_FLAG_TILEABLE_HORIZONTAL;
+		tileable_vertical = flags & TILE_FLAG_TILEABLE_VERTICAL;
+		has_color = flags & TILE_FLAG_HAS_COLOR;
+		has_scale = flags & TILE_FLAG_HAS_SCALE;
+		has_align_style = flags & TILE_FLAG_HAS_ALIGN_STYLE;
+	} else {
+		if (version >= 1)
+			backface_culling = readU8(is);
+		if (version >= 2) {
+			tileable_horizontal = readU8(is);
+			tileable_vertical = readU8(is);
+		}
+		if (version >= 4)
+			has_color = readU8(is);
+
+		if ((contentfeatures_version < 8) &&
+			((drawtype == NDT_MESH) ||
+			 (drawtype == NDT_FIRELIKE) ||
+			 (drawtype == NDT_LIQUID) ||
+			 (drawtype == NDT_PLANTLIKE)))
+			backface_culling = false;
+	}
+
 	if (has_color) {
 		color.setRed(readU8(is));
 		color.setGreen(readU8(is));
@@ -572,12 +596,192 @@ void ContentFeatures::serialize(std::ostream &os, u16 protocol_version) const
 	writeU8(os, alpha);
 }
 
+void ContentFeatures::deSerializeOld(std::istream &is, int version)
+{
+	if (version == 5) // In PROTOCOL_VERSION 13
+	{
+		name = deSerializeString16(is);
+		groups.clear();
+		u32 groups_size = readU16(is);
+		for(u32 i=0; i<groups_size; i++){
+			std::string name = deSerializeString16(is);
+			int value = readS16(is);
+			groups[name] = value;
+		}
+		drawtype = (enum NodeDrawType)readU8(is);
+
+		visual_scale = readF1000(is);
+		if (readU8(is) != 6)
+			throw SerializationError("unsupported tile count");
+		for (u32 i = 0; i < 6; i++)
+			tiledef[i].deSerialize(is, version, drawtype);
+		if (readU8(is) != CF_SPECIAL_COUNT)
+			throw SerializationError("unsupported CF_SPECIAL_COUNT");
+		for (u32 i = 0; i < CF_SPECIAL_COUNT; i++)
+			tiledef_special[i].deSerialize(is, version, drawtype);
+		setAlphaFromLegacy(readU8(is));
+		post_effect_color.setAlpha(readU8(is));
+		post_effect_color.setRed(readU8(is));
+		post_effect_color.setGreen(readU8(is));
+		post_effect_color.setBlue(readU8(is));
+		param_type = (enum ContentParamType)readU8(is);
+		param_type_2 = (enum ContentParamType2)readU8(is);
+		is_ground_content = readU8(is);
+		light_propagates = readU8(is);
+		sunlight_propagates = readU8(is);
+		walkable = readU8(is);
+		pointable = readU8(is);
+		diggable = readU8(is);
+		climbable = readU8(is);
+		buildable_to = readU8(is);
+		deSerializeString16(is); // legacy: used to be metadata_name
+		liquid_type = (enum LiquidType)readU8(is);
+		liquid_alternative_flowing = deSerializeString16(is);
+		liquid_alternative_source = deSerializeString16(is);
+		liquid_viscosity = readU8(is);
+		light_source = readU8(is);
+		light_source = MYMIN(light_source, LIGHT_MAX);
+		damage_per_second = readU32(is);
+		node_box.deSerialize(is);
+		selection_box.deSerialize(is);
+		legacy_facedir_simple = readU8(is);
+		legacy_wallmounted = readU8(is);
+		sound_footstep.deSerialize(is, version);
+		sound_dig.deSerialize(is, version);
+		sound_dug.deSerialize(is, version);
+	} else if (version == 6) {
+		name = deSerializeString16(is);
+		groups.clear();
+		u32 groups_size = readU16(is);
+		for (u32 i = 0; i < groups_size; i++) {
+			std::string name = deSerializeString16(is);
+			int	value = readS16(is);
+			groups[name] = value;
+		}
+		drawtype = (enum NodeDrawType)readU8(is);
+		visual_scale = readF1000(is);
+		if (readU8(is) != 6)
+			throw SerializationError("unsupported tile count");
+		for (u32 i = 0; i < 6; i++)
+			tiledef[i].deSerialize(is, version, drawtype);
+		// CF_SPECIAL_COUNT in version 6 = 2
+		if (readU8(is) != 2)
+			throw SerializationError("unsupported CF_SPECIAL_COUNT");
+		for (u32 i = 0; i < 2; i++)
+			tiledef_special[i].deSerialize(is, version, drawtype);
+		setAlphaFromLegacy(readU8(is));
+		post_effect_color.setAlpha(readU8(is));
+		post_effect_color.setRed(readU8(is));
+		post_effect_color.setGreen(readU8(is));
+		post_effect_color.setBlue(readU8(is));
+		param_type = (enum ContentParamType)readU8(is);
+		param_type_2 = (enum ContentParamType2)readU8(is);
+		is_ground_content = readU8(is);
+		light_propagates = readU8(is);
+		sunlight_propagates = readU8(is);
+		walkable = readU8(is);
+		pointable = readU8(is);
+		diggable = readU8(is);
+		climbable = readU8(is);
+		buildable_to = readU8(is);
+		deSerializeString16(is); // legacy: used to be metadata_name
+		liquid_type = (enum LiquidType)readU8(is);
+		liquid_alternative_flowing = deSerializeString16(is);
+		liquid_alternative_source = deSerializeString16(is);
+		liquid_viscosity = readU8(is);
+		liquid_renewable = readU8(is);
+		light_source = readU8(is);
+		damage_per_second = readU32(is);
+		node_box.deSerialize(is);
+		selection_box.deSerialize(is);
+		legacy_facedir_simple = readU8(is);
+		legacy_wallmounted = readU8(is);
+		sound_footstep.deSerialize(is, version);
+		sound_dig.deSerialize(is, version);
+		sound_dug.deSerialize(is, version);
+		rightclickable = readU8(is);
+		drowning = readU8(is);
+		leveled = readU8(is);
+		liquid_range = readU8(is);
+	} else if (version == 7 || version == 8){
+		name = deSerializeString16(is);
+		groups.clear();
+		u32 groups_size = readU16(is);
+		for (u32 i = 0; i < groups_size; i++) {
+			std::string name = deSerializeString16(is);
+			int value = readS16(is);
+			groups[name] = value;
+		}
+		drawtype = (enum NodeDrawType) readU8(is);
+
+		visual_scale = readF1000(is);
+		if (readU8(is) != 6)
+			throw SerializationError("unsupported tile count");
+		for (u32 i = 0; i < 6; i++)
+			tiledef[i].deSerialize(is, version, drawtype);
+		if (readU8(is) != CF_SPECIAL_COUNT)
+			throw SerializationError("unsupported CF_SPECIAL_COUNT");
+		for (u32 i = 0; i < CF_SPECIAL_COUNT; i++)
+			tiledef_special[i].deSerialize(is, version, drawtype);
+		setAlphaFromLegacy(readU8(is));
+		post_effect_color.setAlpha(readU8(is));
+		post_effect_color.setRed(readU8(is));
+		post_effect_color.setGreen(readU8(is));
+		post_effect_color.setBlue(readU8(is));
+		param_type = (enum ContentParamType) readU8(is);
+		param_type_2 = (enum ContentParamType2) readU8(is);
+		is_ground_content = readU8(is);
+		light_propagates = readU8(is);
+		sunlight_propagates = readU8(is);
+		walkable = readU8(is);
+		pointable = readU8(is);
+		diggable = readU8(is);
+		climbable = readU8(is);
+		buildable_to = readU8(is);
+		deSerializeString16(is); // legacy: used to be metadata_name
+		liquid_type = (enum LiquidType) readU8(is);
+		liquid_alternative_flowing = deSerializeString16(is);
+		liquid_alternative_source = deSerializeString16(is);
+		liquid_viscosity = readU8(is);
+		liquid_renewable = readU8(is);
+		light_source = readU8(is);
+		light_source = MYMIN(light_source, LIGHT_MAX);
+		damage_per_second = readU32(is);
+		node_box.deSerialize(is);
+		selection_box.deSerialize(is);
+		legacy_facedir_simple = readU8(is);
+		legacy_wallmounted = readU8(is);
+		sound_footstep.deSerialize(is, version);
+		sound_dig.deSerialize(is, version);
+		sound_dug.deSerialize(is, version);
+		rightclickable = readU8(is);
+		drowning = readU8(is);
+		leveled = readU8(is);
+		liquid_range = readU8(is);
+		waving = readU8(is);
+		try {
+			mesh = deSerializeString16(is);
+			collision_box.deSerialize(is);
+			floodable = readU8(is);
+			u16 connects_to_size = readU16(is);
+			connects_to_ids.clear();
+			for (u16 i = 0; i < connects_to_size; i++)
+				connects_to_ids.push_back(readU16(is));
+			connect_sides = readU8(is);
+		} catch (SerializationError &e) {};
+	}else{
+		throw SerializationError("unsupported ContentFeatures version");
+	}
+}
+
 void ContentFeatures::deSerialize(std::istream &is)
 {
 	// version detection
 	const u8 version = readU8(is);
-	if (version < CONTENTFEATURES_VERSION)
+	if (version < 9) {
-		throw SerializationError("unsupported ContentFeatures version");
+		deSerializeOld(is, version);
+		return;
+	}
 
 	// general
 	name = deSerializeString16(is);
@@ -594,7 +798,10 @@ void ContentFeatures::deSerialize(std::istream &is)
 	// visual
 	drawtype = (enum NodeDrawType) readU8(is);
 	mesh = deSerializeString16(is);
-	visual_scale = readF32(is);
+	if (version > 12)
+		visual_scale = readF32(is);
+	else
+		visual_scale = readF1000(is);
 	if (readU8(is) != 6)
 		throw SerializationError("unsupported tile count");
 	for (TileDef &td : tiledef)

src/nodedef.h

@@ -423,6 +423,7 @@ struct ContentFeatures
 	void reset();
 	void serialize(std::ostream &os, u16 protocol_version) const;
 	void deSerialize(std::istream &is);
+	void deSerializeOld(std::istream &is, int version);
 	void serializeOld(std::ostream &os, u16 protocol_version) const;
 
 	/*

src/object_properties.cpp

@@ -222,51 +222,72 @@ void ObjectProperties::serialize(std::ostream &os, u16 protocol_version) const
 void ObjectProperties::deSerialize(std::istream &is)
 {
 	int version = readU8(is);
-	if (version != 4)
+	if (version != 1 && version != 4)
 		throw SerializationError("unsupported ObjectProperties version");
 
-	hp_max = readU16(is);
+	// Another approximate protocol version.
-	physical = readU8(is);
+	const u16 protocol_version = version == 1 ? 32 : 37;
-	readU32(is); // removed property (weight)
+
-	collisionbox.MinEdge = readV3F32(is);
-	collisionbox.MaxEdge = readV3F32(is);
-	selectionbox.MinEdge = readV3F32(is);
-	selectionbox.MaxEdge = readV3F32(is);
-	pointable = readU8(is);
-	visual = deSerializeString16(is);
-	visual_size = readV3F32(is);
-	textures.clear();
-	u32 texture_count = readU16(is);
-	for (u32 i = 0; i < texture_count; i++){
-		textures.push_back(deSerializeString16(is));
-	}
-	spritediv = readV2S16(is);
-	initial_sprite_basepos = readV2S16(is);
-	is_visible = readU8(is);
-	makes_footstep_sound = readU8(is);
-	automatic_rotate = readF32(is);
-	mesh = deSerializeString16(is);
-	colors.clear();
-	u32 color_count = readU16(is);
-	for (u32 i = 0; i < color_count; i++){
-		colors.push_back(readARGB8(is));
-	}
-	collideWithObjects = readU8(is);
-	stepheight = readF32(is);
-	automatic_face_movement_dir = readU8(is);
-	automatic_face_movement_dir_offset = readF32(is);
-	backface_culling = readU8(is);
-	nametag = deSerializeString16(is);
-	nametag_color = readARGB8(is);
-	automatic_face_movement_max_rotation_per_sec = readF32(is);
-	infotext = deSerializeString16(is);
-	wield_item = deSerializeString16(is);
-	glow = readS8(is);
-	breath_max = readU16(is);
-	eye_height = readF32(is);
-	zoom_fov = readF32(is);
-	use_texture_alpha = readU8(is);
 	try {
+		hp_max = readU16(is);
+		physical = readU8(is);
+		readU32(is); // removed property (weight)
+		collisionbox.MinEdge = readV3F(is, protocol_version);
+		collisionbox.MaxEdge = readV3F(is, protocol_version);
+		if (version >= 4) {
+			selectionbox.MinEdge = readV3F32(is);
+			selectionbox.MaxEdge = readV3F32(is);
+			pointable = readU8(is);
+		} else {
+			selectionbox.MinEdge = collisionbox.MinEdge;
+			selectionbox.MaxEdge = collisionbox.MaxEdge;
+			pointable = true;
+		}
+		visual = deSerializeString16(is);
+		if (version == 1) {
+			v2f size = readV2F1000(is);
+			visual_size = v3f(size.X, size.Y, size.X);
+		} else {
+			visual_size = readV3F32(is);
+		}
+		textures.clear();
+		u32 texture_count = readU16(is);
+		for (u32 i = 0; i < texture_count; i++){
+			textures.push_back(deSerializeString16(is));
+		}
+		spritediv = readV2S16(is);
+		initial_sprite_basepos = readV2S16(is);
+		is_visible = readU8(is);
+		makes_footstep_sound = readU8(is);
+		automatic_rotate = readF(is, protocol_version);
+		mesh = deSerializeString16(is);
+		colors.clear();
+		u32 color_count = readU16(is);
+		for (u32 i = 0; i < color_count; i++){
+			colors.push_back(readARGB8(is));
+		}
+		collideWithObjects = readU8(is);
+		stepheight = readF(is, protocol_version);
+		automatic_face_movement_dir = readU8(is);
+		automatic_face_movement_dir_offset = readF(is, protocol_version);
+		backface_culling = readU8(is);
+		nametag = deSerializeString16(is);
+		nametag_color = readARGB8(is);
+		automatic_face_movement_max_rotation_per_sec = readF(is,
+			protocol_version);
+		infotext = deSerializeString16(is);
+		wield_item = deSerializeString16(is);
+
+		// The "glow" property exists in MultiCraft 1.
+		glow = readS8(is);
+		if (version == 1)
+			return;
+
+		breath_max = readU16(is);
+		eye_height = readF32(is);
+		zoom_fov = readF32(is);
+		use_texture_alpha = readU8(is);
+
 		damage_texture_modifier = deSerializeString16(is);
 		u8 tmp = readU8(is);
 		if (is.eof())

src/particles.cpp

@@ -41,16 +41,18 @@ void ParticleParameters::serialize(std::ostream &os, u16 protocol_ver) const
 
 void ParticleParameters::deSerialize(std::istream &is, u16 protocol_ver)
 {
-	pos                = readV3F32(is);
+	pos                = readV3F(is, protocol_ver);
-	vel                = readV3F32(is);
+	vel                = readV3F(is, protocol_ver);
-	acc                = readV3F32(is);
+	acc                = readV3F(is, protocol_ver);
-	expirationtime     = readF32(is);
+	expirationtime     = readF(is, protocol_ver);
-	size               = readF32(is);
+	size               = readF(is, protocol_ver);
 	collisiondetection = readU8(is);
 	texture            = deSerializeString32(is);
 	vertical           = readU8(is);
 	collision_removal  = readU8(is);
-	animation.deSerialize(is, 6); /* NOT the protocol ver */
+	animation.deSerializeWithProtoVer(is, protocol_ver);
+
+	// TODO: Ensure this doesn't error
 	glow               = readU8(is);
 	object_collision   = readU8(is);
 	// This is kinda awful

src/sound.h

@@ -56,9 +56,16 @@ struct SimpleSoundSpec
 	void deSerialize(std::istream &is, u8 cf_version)
 	{
 		name = deSerializeString16(is);
-		gain = readF32(is);
+		if (cf_version > 12) {
-		pitch = readF32(is);
+			gain = readF32(is);
-		fade = readF32(is);
+			pitch = readF32(is);
+			fade = readF32(is);
+		} else {
+			// Minetest 0.4 compatibility
+			gain = readF1000(is);
+			pitch = 1.0f;
+			fade = 0.0f;
+		}
 	}
 
 	std::string name;

src/tileanimation.cpp

@@ -49,17 +49,42 @@ void TileAnimationParams::deSerialize(std::istream &is, u8 tiledef_version)
 {
 	type = (TileAnimationType) readU8(is);
 
-	if (type == TAT_VERTICAL_FRAMES) {
+	FATAL_ERROR_IF(tiledef_version >= 25, "TileAnimationParams::deSerialize "
+		"called with what is probably a protocol version.");
+
+	// Approximate protocol version
+	u16 protocol_version = tiledef_version >= 6 ? 37 : 32;
+
+	if (type == TAT_VERTICAL_FRAMES || tiledef_version <= 2) {
 		vertical_frames.aspect_w = readU16(is);
 		vertical_frames.aspect_h = readU16(is);
-		vertical_frames.length = fabs(readF32(is));
+		// Don't hang if a negative length is sent
+		vertical_frames.length = fabs(readF(is, protocol_version));
 	} else if (type == TAT_SHEET_2D) {
 		sheet_2d.frames_w = readU8(is);
 		sheet_2d.frames_h = readU8(is);
-		sheet_2d.frame_length = fabs(readF32(is));
+		sheet_2d.frame_length = fabs(readF(is, protocol_version));
 	}
 }
 
+void TileAnimationParams::deSerializeWithProtoVer(std::istream &is,
+		u16 protocol_version)
+{
+	u8 tiledef_version;
+	if (protocol_version >= 37)
+		tiledef_version = 6;
+	else if (protocol_version >= 30)
+		tiledef_version = 4;
+	else if (protocol_version >= 29)
+		tiledef_version = 3;
+	else if (protocol_version >= 26)
+		tiledef_version = 2;
+	else
+		tiledef_version = 1;
+
+	deSerialize(is, tiledef_version);
+}
+
 void TileAnimationParams::determineParams(v2u32 texture_size, int *frame_count,
 		int *frame_length_ms, v2u32 *frame_size) const
 {

src/tileanimation.h

@@ -52,6 +52,7 @@ struct TileAnimationParams
 
 	void serialize(std::ostream &os, u8 tiledef_version) const;
 	void deSerialize(std::istream &is, u8 tiledef_version);
+	void deSerializeWithProtoVer(std::istream &is, u16 protocol_version);
 	void determineParams(v2u32 texture_size, int *frame_count, int *frame_length_ms,
 			v2u32 *frame_size) const;
 	void getTextureModifer(std::ostream &os, v2u32 texture_size, int frame) const;

src/tool.cpp

@@ -92,10 +92,13 @@ void ToolCapabilities::serialize(std::ostream &os, u16 protocol_version) const
 void ToolCapabilities::deSerialize(std::istream &is)
 {
 	int version = readU8(is);
-	if (version < 4)
+	if (version != 1 && version != 2 && version < 4)
 		throw SerializationError("unsupported ToolCapabilities version");
 
-	full_punch_interval = readF32(is);
+	if (version > 3)
+		full_punch_interval = readF32(is);
+	else
+		full_punch_interval = readF1000(is);
 	max_drop_level = readS16(is);
 	groupcaps.clear();
 	u32 groupcaps_size = readU32(is);
@@ -107,7 +110,11 @@ void ToolCapabilities::deSerialize(std::istream &is)
 		u32 times_size = readU32(is);
 		for(u32 i = 0; i < times_size; i++) {
 			int level = readS16(is);
-			float time = readF32(is);
+			float time;
+			if (version > 3)
+				time = readF32(is);
+			else
+				time = readF1000(is);
 			cap.times[level] = time;
 		}
 		groupcaps[name] = cap;