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Merged
electronicboy merged 14 commits into from
Jun 16, 2026
Merged

Minecraft 26.2 #1807

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cf1dd8d
26.2-snapshot-2
RealBauHD Apr 11, 2026
241e44d
26.2-snapshot-3
RealBauHD Apr 21, 2026
e23b6b2
26.2-snapshot-4
RealBauHD Apr 21, 2026
8548a22
26.2-pre-1
RealBauHD May 26, 2026
eab21a6
26.2-pre-3
RealBauHD Jun 2, 2026
e010a95
26.2-pre-4
RealBauHD Jun 5, 2026
b19f12c
chore: set online mode and session id
RealBauHD Jun 5, 2026
46f22c0
fix: checkstyle
RealBauHD Jun 8, 2026
b048133
26.2-pre-5
RealBauHD Jun 8, 2026
c3e0147
26.2-pre-6
RealBauHD Jun 10, 2026
b293486
26.2-rc-1
RealBauHD Jun 11, 2026
65207e2
26.2-rc-2
RealBauHD Jun 12, 2026
ec19db8
unregister old color argument in 26.2
RealBauHD Jun 16, 2026
6a16dfd
26.2
RealBauHD Jun 16, 2026
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3 changes: 2 additions & 1 deletion api/src/main/java/com/velocitypowered/api/network/ProtocolVersion.java
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Original file line number Diff line number Diff line change
Expand Up @@ -95,7 +95,8 @@ public boolean isSupported() {
MINECRAFT_1_21_7(772, "1.21.7", "1.21.8"),
MINECRAFT_1_21_9(773, "1.21.9", "1.21.10"),
MINECRAFT_1_21_11(774, "1.21.11"),
MINECRAFT_26_1(775, "26.1", "26.1.1", "26.1.2");
MINECRAFT_26_1(775, "26.1", "26.1.1", "26.1.2"),
MINECRAFT_26_2(776, "26.2");

private static final int SNAPSHOT_BIT = 30;

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5 changes: 4 additions & 1 deletion .../src/main/java/com/velocitypowered/proxy/connection/backend/TransitionSessionHandler.java
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Expand Up @@ -89,7 +89,7 @@ public boolean handle(KeepAlivePacket packet) {

@Override
public boolean handle(JoinGamePacket packet) {
MinecraftConnection smc = serverConn.ensureConnected();
final MinecraftConnection smc = serverConn.ensureConnected();
final RegisteredServer previousServer = serverConn.getPreviousServer().orElse(null);
final ConnectedPlayer player = serverConn.getPlayer();
final VelocityServerConnection existingConnection = player.getConnectedServer();
Expand All @@ -106,6 +106,9 @@ public boolean handle(JoinGamePacket packet) {
// Reset Tablist header and footer to prevent desync
player.clearPlayerListHeaderAndFooter();

// Override online mode
packet.setOnlineMode(player.isOnlineMode());

// The goods are in hand! We got JoinGame. Let's transition completely to the new state.
smc.setAutoReading(false);
server.getEventManager()
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3 changes: 3 additions & 0 deletions proxy/src/main/java/com/velocitypowered/proxy/connection/client/AuthSessionHandler.java
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Expand Up @@ -236,6 +236,9 @@ private void completeLoginProtocolPhaseAndInitialize(ConnectedPlayer player) {
success.setUsername(player.getUsername());
success.setProperties(player.getGameProfileProperties());
success.setUuid(player.getUniqueId());
if (inbound.getProtocolVersion().noLessThan(ProtocolVersion.MINECRAFT_26_2)) {
success.setSessionId(UUID.randomUUID()); // use random uuid for now

@electronicboy electronicboy Jun 15, 2026

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Interestingly, mojang seems to be a "use the same session ID for everybody but regenerate it when the server is empty"

https://mcsrc.dev/1/26.2-rc-2/net/minecraft/server/network/ServerConnectionListener#L225

https://mcsrc.dev/1/26.2-rc-2/net/minecraft/server/network/ServerConnectionListener#L241

This is used purely for metrics on mojangs side, I guess the "good behavior" here would probably be to reproduce that logic

@WouterGritter WouterGritter Jun 15, 2026

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I'm wondering what Mojang sees as a "session" in this case. Does a new session occur the moment the last player online disconnects (or the moment the first player connects, going from 0 -> 1 players, effectively the same), or does a new session only occur when the server was "paused" due to it being empty (correct me if I'm wrong, but a vanilla server should pause processing ticks after no players have been online for x seconds (30?))

If it's the latter that's harder to match in Velocity... Though regardless, if the client expects the session ID to be the same for everyone connected at the same time, it's most likely better to match this behavior. Easiest is to just generate a session ID on boot.

@WouterGritter WouterGritter Jun 15, 2026

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(or uh, grab the session ID from the backend? is that possible here? why do we need to generate our own in velocity land?)

@electronicboy electronicboy Jun 15, 2026

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session ID is sent from the proxy long before we have a backend, so that's not an option;

And I guess their modal is basically single player servers where people join in the eveing, have a "play session" together, and leave, and come back in a day or a few hours or whatever. For a larger server which always had players on that would always be shared

@electronicboy electronicboy Jun 15, 2026

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Then again, doesn't really translate to proxies, do we just sent 0,0? I'll ask mojang...

@WouterGritter WouterGritter Jun 15, 2026 •
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I have a hunch the session ID will be used in the new friends feature that got dropped from the 26.2 release. I'd guess you would be able to easily add players that are on the same server as you. As this will be done through Mojang's own API, the client can just report the session UUID it got from the connected server, and Mojang can match players against the same session UUID and consider them in the same server.

This would break with the current random UUID per connection approach (and also a zero UUID as youre suggesting). Though, it might also be useful for plugins to be able to control this. I could imagine a feature where certain players want to turn this off (staff? content people?). A plugin would be able to check a permission, and override the session UUID with a random one. Though that's all assuming it will be used for the dropped social/friends feature.

}
mcConnection.write(success);

loginState = State.SUCCESS_SENT;
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15 changes: 14 additions & 1 deletion proxy/src/main/java/com/velocitypowered/proxy/protocol/packet/JoinGamePacket.java
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Expand Up @@ -52,6 +52,7 @@ public class JoinGamePacket implements MinecraftPacket {
private @Nullable Pair<String, Long> lastDeathPosition; // 1.19+
private int portalCooldown; // 1.20+
private int seaLevel; // 1.21.2+
private boolean onlineMode; // 26.2+
private boolean enforcesSecureChat; // 1.20.5+

public int getEntityId() {
Expand Down Expand Up @@ -190,6 +191,10 @@ public void setSeaLevel(int seaLevel) {
this.seaLevel = seaLevel;
}

public void setOnlineMode(boolean onlineMode) {
this.onlineMode = onlineMode;
}

public boolean getEnforcesSecureChat() {
return this.enforcesSecureChat;
}
Expand All @@ -213,7 +218,7 @@ public String toString() {
dimensionInfo + '\'' + ", currentDimensionData='" + currentDimensionData + '\'' +
", previousGamemode=" + previousGamemode + ", simulationDistance=" + simulationDistance +
", lastDeathPosition='" + lastDeathPosition + '\'' + ", portalCooldown=" + portalCooldown +
", seaLevel=" + seaLevel +
", seaLevel=" + seaLevel + ", onlineMode=" + this.onlineMode +
'}';
}

Expand Down Expand Up @@ -358,6 +363,10 @@ private void decode1202Up(ByteBuf buf, ProtocolVersion version) {
this.seaLevel = ProtocolUtils.readVarInt(buf);
}

if (version.noLessThan(ProtocolVersion.MINECRAFT_26_2)) {
this.onlineMode = buf.readBoolean();
}

if (version.noLessThan(ProtocolVersion.MINECRAFT_1_20_5)) {
this.enforcesSecureChat = buf.readBoolean();
}
Expand Down Expand Up @@ -510,6 +519,10 @@ private void encode1202Up(ByteBuf buf, ProtocolVersion version) {
ProtocolUtils.writeVarInt(buf, seaLevel);
}

if (version.noLessThan(ProtocolVersion.MINECRAFT_26_2)) {
buf.writeBoolean(this.onlineMode);
}

if (version.noLessThan(ProtocolVersion.MINECRAFT_1_20_5)) {
buf.writeBoolean(this.enforcesSecureChat);
}
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13 changes: 13 additions & 0 deletions proxy/src/main/java/com/velocitypowered/proxy/protocol/packet/ServerLoginSuccessPacket.java
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Expand Up @@ -35,6 +35,7 @@ public class ServerLoginSuccessPacket implements MinecraftPacket {
private @Nullable UUID uuid;
private @Nullable String username;
private @Nullable List<GameProfile.Property> properties;
private @Nullable UUID sessionId;
private static final boolean strictErrorHandling = VelocityProperties
.readBoolean("velocity.strictErrorHandling", true);

Expand Down Expand Up @@ -68,6 +69,10 @@ public void setProperties(List<GameProfile.Property> properties) {
this.properties = properties;
}

public void setSessionId(@Nullable UUID sessionId) {
this.sessionId = sessionId;
}

@Override
public String toString() {
return "ServerLoginSuccess{"
Expand Down Expand Up @@ -96,6 +101,10 @@ public void decode(ByteBuf buf, ProtocolUtils.Direction direction, ProtocolVersi
if (version == ProtocolVersion.MINECRAFT_1_20_5 || version == ProtocolVersion.MINECRAFT_1_21) {
buf.readBoolean();
}

if (version.noLessThan(ProtocolVersion.MINECRAFT_26_2)) {
this.sessionId = ProtocolUtils.readUuid(buf);
}
}

@Override
Expand Down Expand Up @@ -127,6 +136,10 @@ public void encode(ByteBuf buf, ProtocolUtils.Direction direction, ProtocolVersi
if (version == ProtocolVersion.MINECRAFT_1_20_5 || version == ProtocolVersion.MINECRAFT_1_21) {
buf.writeBoolean(strictErrorHandling);
}

if (version.noLessThan(ProtocolVersion.MINECRAFT_26_2)) {
ProtocolUtils.writeUuid(buf, this.sessionId);
}
}

@Override
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4 changes: 3 additions & 1 deletion ...in/java/com/velocitypowered/proxy/protocol/packet/brigadier/ArgumentPropertyRegistry.java
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Expand Up @@ -24,6 +24,7 @@
import static com.velocitypowered.api.network.ProtocolVersion.MINECRAFT_1_20_5;
import static com.velocitypowered.api.network.ProtocolVersion.MINECRAFT_1_21_5;
import static com.velocitypowered.api.network.ProtocolVersion.MINECRAFT_1_21_6;
import static com.velocitypowered.api.network.ProtocolVersion.MINECRAFT_26_2;
import static com.velocitypowered.proxy.protocol.packet.brigadier.ArgumentIdentifier.id;
import static com.velocitypowered.proxy.protocol.packet.brigadier.ArgumentIdentifier.mapSet;
import static com.velocitypowered.proxy.protocol.packet.brigadier.DoubleArgumentPropertySerializer.DOUBLE;
Expand Down Expand Up @@ -207,7 +208,7 @@ public void serialize(BoolArgumentType object, ByteBuf buf,
empty(id("minecraft:block_predicate", mapSet(MINECRAFT_1_19, 13)));
empty(id("minecraft:item_stack", mapSet(MINECRAFT_1_19, 14)));
empty(id("minecraft:item_predicate", mapSet(MINECRAFT_1_19, 15)));
empty(id("minecraft:color", mapSet(MINECRAFT_1_19, 16)));
empty(id("minecraft:color", mapSet(MINECRAFT_26_2, -1), mapSet(MINECRAFT_1_19, 16))); // renamed to team_color in 26.2
empty(id("minecraft:component", mapSet(MINECRAFT_1_21_6, 18), mapSet(MINECRAFT_1_19, 17)));
empty(id("minecraft:style", mapSet(MINECRAFT_1_21_6, 19), mapSet(MINECRAFT_1_20_3, 18))); // added 1.20.3
empty(id("minecraft:message", mapSet(MINECRAFT_1_21_6, 20), mapSet(MINECRAFT_1_20_3, 19), mapSet(MINECRAFT_1_19, 18)));
Expand Down Expand Up @@ -281,6 +282,7 @@ public void serialize(BoolArgumentType object, ByteBuf buf,

empty(id("minecraft:hex_color", mapSet(MINECRAFT_1_21_6, 17))); // added in 1.21.6
empty(id("minecraft:dialog", mapSet(MINECRAFT_1_21_6, 55))); // added in 1.21.6
empty(id("minecraft:team_color", mapSet(MINECRAFT_26_2, 16))); // renamed from color in 26.2

// Crossstitch support
register(id("crossstitch:mod_argument", mapSet(MINECRAFT_1_19, -256)), ModArgumentProperty.class, MOD);
Expand Down