Packet Play Client World Border

Version	ID
1.8.X	0x44
1.9	0x35
1.12	0x37
1.12.1	0x38
1.13.1	0x3B
1.14.4	0x3D
1.15.2	0x3E

1.15.2

Packet ID	State	Bound To	Field Name		Field Type	Notes
0x3E	Play	Client	Action		VarInt Enum	Determines the format of the rest of the packet
			Action	Field Name
			0: set size	Diameter	Double	Length of a single side of the world border, in meters
			1: lerp size	Old Diameter	Double	Current length of a single side of the world border, in meters
				New Diameter	Double	Target length of a single side of the world border, in meters
				Speed	VarLong	Number of real-time milliseconds until New Diameter is reached. It appears that Notchian server does not sync world border speed to game ticks, so it gets out of sync with server lag. If the world border is not moving, this is set to 0.
			2: set center	X	Double
			2: set center	Z	Double
			3: initialize	X	Double
				Z	Double
				Old Diameter	Double	Current length of a single side of the world border, in meters
				New Diameter	Double	Target length of a single side of the world border, in meters
				Speed	VarLong	Number of real-time milliseconds until New Diameter is reached. It appears that Notchian server does not sync world border speed to game ticks, so it gets out of sync with server lag. If the world border is not moving, this is set to 0.
				Portal Teleport Boundary	VarInt	Resulting coordinates from a portal teleport are limited to ±value. Usually 29999984.
				Warning Time	VarInt	In seconds as set by `/worldborder warning time`
				Warning Blocks	VarInt	In meters
			4: set warning time	Warning Time	VarInt	In seconds as set by `/worldborder warning time`
			5: set warning blocks	Warning Blocks	VarInt	In meters

1.14.4

Packet ID	State	Bound To	Field Name		Field Type	Notes
0x3D	Play	Client	Action		VarInt Enum	Determines the format of the rest of the packet
			Action	Field Name
			0: set size	Diameter	Double	Length of a single side of the world border, in meters
			1: lerp size	Old Diameter	Double	Current length of a single side of the world border, in meters
				New Diameter	Double	Target length of a single side of the world border, in meters
				Speed	VarLong	Number of real-time milliseconds until New Diameter is reached. It appears that Notchian server does not sync world border speed to game ticks, so it gets out of sync with server lag. If the world border is not moving, this is set to 0.
			2: set center	X	Double
			2: set center	Z	Double
			3: initialize	X	Double
				Z	Double
				Old Diameter	Double	Current length of a single side of the world border, in meters
				New Diameter	Double	Target length of a single side of the world border, in meters
				Speed	VarLong	Number of real-time milliseconds until New Diameter is reached. It appears that Notchian server does not sync world border speed to game ticks, so it gets out of sync with server lag. If the world border is not moving, this is set to 0.
				Portal Teleport Boundary	VarInt	Resulting coordinates from a portal teleport are limited to ±value. Usually 29999984.
				Warning Time	VarInt	In seconds as set by `/worldborder warning time`
				Warning Blocks	VarInt	In meters
			4: set warning time	Warning Time	VarInt	In seconds as set by `/worldborder warning time`
			5: set warning blocks	Warning Blocks	VarInt	In meters

1.13.2

Packet ID	State	Bound To	Field Name		Field Type	Notes
0x3B	Play	Client	Action		VarInt Enum	Determines the format of the rest of the packet
			Action	Field Name
			0: set size	Diameter	Double	Length of a single side of the world border, in meters
			1: lerp size	Old Diameter	Double	Current length of a single side of the world border, in meters
				New Diameter	Double	Target length of a single side of the world border, in meters
				Speed	VarLong	Number of real-time milliseconds until New Diameter is reached. It appears that Notchian server does not sync world border speed to game ticks, so it gets out of sync with server lag. If the world border is not moving, this is set to 0.
			2: set center	X	Double
			2: set center	Z	Double
			3: initialize	X	Double
				Z	Double
				Old Diameter	Double	Current length of a single side of the world border, in meters
				New Diameter	Double	Target length of a single side of the world border, in meters
				Speed	VarLong	Number of real-time milliseconds until New Diameter is reached. It appears that Notchian server does not sync world border speed to game ticks, so it gets out of sync with server lag. If the world border is not moving, this is set to 0.
				Portal Teleport Boundary	VarInt	Resulting coordinates from a portal teleport are limited to ±value. Usually 29999984.
				Warning Time	VarInt	In seconds as set by `/worldborder warning time`
				Warning Blocks	VarInt	In meters
			4: set warning time	Warning Time	VarInt	In seconds as set by `/worldborder warning time`
			5: set warning blocks	Warning Blocks	VarInt	In meters

1.13.1

Packet ID	State	Bound To	Field Name		Field Type	Notes
0x3B	Play	Client	Action		VarInt Enum	Determines the format of the rest of the packet
			Action	Field Name
			0: set size	Diameter	Double	Length of a single side of the world border, in meters
			1: lerp size	Old Diameter	Double	Current length of a single side of the world border, in meters
				New Diameter	Double	Target length of a single side of the world border, in meters
				Speed	VarLong	Number of real-time milliseconds until New Diameter is reached. It appears that Notchian server does not sync world border speed to game ticks, so it gets out of sync with server lag. If the world border is not moving, this is set to 0.
			2: set center	X	Double
			2: set center	Z	Double
			3: initialize	X	Double
				Z	Double
				Old Diameter	Double	Current length of a single side of the world border, in meters
				New Diameter	Double	Target length of a single side of the world border, in meters
				Speed	VarLong	Number of real-time milliseconds until New Diameter is reached. It appears that Notchian server does not sync world border speed to game ticks, so it gets out of sync with server lag. If the world border is not moving, this is set to 0.
				Portal Teleport Boundary	VarInt	Resulting coordinates from a portal teleport are limited to ±value. Usually 29999984.
				Warning Time	VarInt	In seconds as set by `/worldborder warning time`
				Warning Blocks	VarInt	In meters
			4: set warning time	Warning Time	VarInt	In seconds as set by `/worldborder warning time`
			5: set warning blocks	Warning Blocks	VarInt	In meters

1.12.2

Packet ID	State	Bound To	Field Name		Field Type	Notes
0x38	Play	Client	Action		VarInt Enum	Determines the format of the rest of the packet
			Action	Field Name
			0: set size	Diameter	Double	Length of a single side of the world border, in meters
			1: lerp size	Old Diameter	Double	Current length of a single side of the world border, in meters
				New Diameter	Double	Target length of a single side of the world border, in meters
				Speed	VarLong	Number of real-time milliseconds until New Diameter is reached. It appears that Notchian server does not sync world border speed to game ticks, so it gets out of sync with server lag. If the world border is not moving, this is set to 0.
			2: set center	X	Double
			2: set center	Z	Double
			3: initialize	X	Double
				Z	Double
				Old Diameter	Double	Current length of a single side of the world border, in meters
				New Diameter	Double	Target length of a single side of the world border, in meters
				Speed	VarLong	Number of real-time milliseconds until New Diameter is reached. It appears that Notchian server does not sync world border speed to game ticks, so it gets out of sync with server lag. If the world border is not moving, this is set to 0.
				Portal Teleport Boundary	VarInt	Resulting coordinates from a portal teleport are limited to ±value. Usually 29999984.
				Warning Time	VarInt	In seconds as set by `/worldborder warning time`
				Warning Blocks	VarInt	In meters
			4: set warning time	Warning Time	VarInt	In seconds as set by `/worldborder warning time`
			5: set warning blocks	Warning Blocks	VarInt	In meters

1.12.1

Packet ID	State	Bound To	Field Name		Field Type	Notes
0x38	Play	Client	Action		VarInt Enum	Determines the format of the rest of the packet
			Action	Field Name
			0: set size	Diameter	Double	Length of a single side of the world border, in meters
			1: lerp size	Old Diameter	Double	Current length of a single side of the world border, in meters
				New Diameter	Double	Target length of a single side of the world border, in meters
				Speed	VarLong	Number of real-time milliseconds until New Diameter is reached. It appears that Notchian server does not sync world border speed to game ticks, so it gets out of sync with server lag. If the world border is not moving, this is set to 0.
			2: set center	X	Double
			2: set center	Z	Double
			3: initialize	X	Double
				Z	Double
				Old Diameter	Double	Current length of a single side of the world border, in meters
				New Diameter	Double	Target length of a single side of the world border, in meters
				Speed	VarLong	Number of real-time milliseconds until New Diameter is reached. It appears that Notchian server does not sync world border speed to game ticks, so it gets out of sync with server lag. If the world border is not moving, this is set to 0.
				Portal Teleport Boundary	VarInt	Resulting coordinates from a portal teleport are limited to ±value. Usually 29999984.
				Warning Time	VarInt	In seconds as set by `/worldborder warning time`
				Warning Blocks	VarInt	In meters
			4: set warning time	Warning Time	VarInt	In seconds as set by `/worldborder warning time`
			5: set warning blocks	Warning Blocks	VarInt	In meters

1.12

Packet ID	State	Bound To	Field Name		Field Type	Notes
0x37	Play	Client	Action		VarInt Enum	Determines the format of the rest of the packet
			Action	Field Name
			0: set size	Diameter	Double	Length of a single side of the world border, in meters
			1: lerp size	Old Diameter	Double	Current length of a single side of the world border, in meters
				New Diameter	Double	Target length of a single side of the world border, in meters
				Speed	VarLong	Number of real-time milliseconds until New Diameter is reached. It appears that Notchian server does not sync world border speed to game ticks, so it gets out of sync with server lag. If the world border is not moving, this is set to 0.
			2: set center	X	Double
			2: set center	Z	Double
			3: initialize	X	Double
				Z	Double
				Old Diameter	Double	Current length of a single side of the world border, in meters
				New Diameter	Double	Target length of a single side of the world border, in meters
				Speed	VarLong	Number of real-time milliseconds until New Diameter is reached. It appears that Notchian server does not sync world border speed to game ticks, so it gets out of sync with server lag. If the world border is not moving, this is set to 0.
				Portal Teleport Boundary	VarInt	Resulting coordinates from a portal teleport are limited to ±value. Usually 29999984.
				Warning Time	VarInt	In seconds as set by `/worldborder warning time`
				Warning Blocks	VarInt	In meters
			4: set warning time	Warning Time	VarInt	In seconds as set by `/worldborder warning time`
			5: set warning blocks	Warning Blocks	VarInt	In meters

1.11.X

Packet ID	State	Bound To	Field Name		Field Type	Notes
0x35	Play	Client	Action		VarInt Enum	Determines the format of the rest of the packet
			Action	Field Name
			0: set size	Diameter	Double	Length of a single side of the world border, in meters
			1: lerp size	Old Diameter	Double	Current length of a single side of the world border, in meters
				New Diameter	Double	Target length of a single side of the world border, in meters
				Speed	VarLong	Number of real-time milliseconds until New Diameter is reached. It appears that Notchian server does not sync world border speed to game ticks, so it gets out of sync with server lag. If the world border is not moving, this is set to 0.
			2: set center	X	Double
			2: set center	Z	Double
			3: initialize	X	Double
				Z	Double
				Old Diameter	Double	Current length of a single side of the world border, in meters
				New Diameter	Double	Target length of a single side of the world border, in meters
				Speed	VarLong	Number of real-time milliseconds until New Diameter is reached. It appears that Notchian server does not sync world border speed to game ticks, so it gets out of sync with server lag. If the world border is not moving, this is set to 0.
				Portal Teleport Boundary	VarInt	Resulting coordinates from a portal teleport are limited to ±value. Usually 29999984.
				Warning Time	VarInt	In seconds as set by `/worldborder warning time`
				Warning Blocks	VarInt	In meters
			4: set warning time	Warning Time	VarInt	In seconds as set by `/worldborder warning time`
			5: set warning blocks	Warning Blocks	VarInt	In meters

1.11

Packet ID	State	Bound To	Field Name		Field Type	Notes
0x35	Play	Client	Action		VarInt Enum	Determines the format of the rest of the packet
			Action	Field Name
			0: set size	Diameter	Double	Length of a single side of the world border, in meters
			1: lerp size	Old Diameter	Double	Current length of a single side of the world border, in meters
				New Diameter	Double	Target length of a single side of the world border, in meters
				Speed	VarLong	Number of real-time milliseconds until New Diameter is reached. It appears that Notchian server does not sync world border speed to game ticks, so it gets out of sync with server lag. If the world border is not moving, this is set to 0.
			2: set center	X	Double
			2: set center	Z	Double
			3: initialize	X	Double
				Z	Double
				Old Diameter	Double	Current length of a single side of the world border, in meters
				New Diameter	Double	Target length of a single side of the world border, in meters
				Speed	VarLong	Number of real-time milliseconds until New Diameter is reached. It appears that Notchian server does not sync world border speed to game ticks, so it gets out of sync with server lag. If the world border is not moving, this is set to 0.
				Portal Teleport Boundary	VarInt	Resulting coordinates from a portal teleport are limited to ±value. Usually 29999984.
				Warning Time	VarInt	In seconds as set by `/worldborder warning time`
				Warning Blocks	VarInt	In meters
			4: set warning time	Warning Time	VarInt	In seconds as set by `/worldborder warning time`
			5: set warning blocks	Warning Blocks	VarInt	In meters

1.11

Packet ID	State	Bound To	Field Name		Field Type	Notes
0x35	Play	Client	Action		VarInt Enum	Determines the format of the rest of the packet
			Action	Field Name
			0: set size	Diameter	Double	Length of a single side of the world border, in meters
			1: lerp size	Old Diameter	Double	Current length of a single side of the world border, in meters
				New Diameter	Double	Target length of a single side of the world border, in meters
				Speed	VarLong	Number of real-time milliseconds until New Diameter is reached. It appears that Notchian server does not sync world border speed to game ticks, so it gets out of sync with server lag. If the world border is not moving, this is set to 0.
			2: set center	X	Double
			2: set center	Z	Double
			3: initialize	X	Double
				Z	Double
				Old Diameter	Double	Current length of a single side of the world border, in meters
				New Diameter	Double	Target length of a single side of the world border, in meters
				Speed	VarLong	Number of real-time milliseconds until New Diameter is reached. It appears that Notchian server does not sync world border speed to game ticks, so it gets out of sync with server lag. If the world border is not moving, this is set to 0.
				Portal Teleport Boundary	VarInt	Resulting coordinates from a portal teleport are limited to ±value. Usually 29999984.
				Warning Time	VarInt	In seconds as set by `/worldborder warning time`
				Warning Blocks	VarInt	In meters
			4: set warning time	Warning Time	VarInt	In seconds as set by `/worldborder warning time`
			5: set warning blocks	Warning Blocks	VarInt	In meters

1.10

Packet ID	State	Bound To	Field Name		Field Type	Notes
0x35	Play	Client	Action		VarInt Enum	Determines the format of the rest of the packet
			Action	Field Name
			0: set size	Diameter	Double	Length of a single side of the world border, in meters
			1: lerp size	Old Diameter	Double	Current length of a single side of the world border, in meters
				New Diameter	Double	Target length of a single side of the world border, in meters
				Speed	VarLong	Number of real-time milliseconds until New Diameter is reached. It appears that Notchian server does not sync world border speed to game ticks, so it gets out of sync with server lag. If the world border is not moving, this is set to 0.
			2: set center	X	Double
			2: set center	Z	Double
			3: initialize	X	Double
				Z	Double
				Old Diameter	Double	Current length of a single side of the world border, in meters
				New Diameter	Double	Target length of a single side of the world border, in meters
				Speed	VarLong	Number of real-time milliseconds until New Diameter is reached. It appears that Notchian server does not sync world border speed to game ticks, so it gets out of sync with server lag. If the world border is not moving, this is set to 0.
				Portal Teleport Boundary	VarInt	Resulting coordinates from a portal teleport are limited to ±value. Usually 29999984.
				Warning Time	VarInt	In seconds as set by `/worldborder warning time`
				Warning Blocks	VarInt	In meters
			4: set warning time	Warning Time	VarInt	In seconds as set by `/worldborder warning time`
			5: set warning blocks	Warning Blocks	VarInt	In meters

1.9.3

Packet ID	State	Bound To	Field Name		Field Type	Notes
0x35	Play	Client	Action		VarInt Enum	Determines the format of the rest of the packet
			Action	Field Name
			0: set size	Diameter	Double	Length of a single side of the world border, in meters
			1: lerp size	Old Diameter	Double	Current length of a single side of the world border, in meters
				New Diameter	Double	Target length of a single side of the world border, in meters
				Speed	VarLong	Number of real-time milliseconds until New Diameter is reached. It appears that Notchian server does not sync world border speed to game ticks, so it gets out of sync with server lag. If the world border is not moving, this is set to 0.
			2: set center	X	Double
			2: set center	Z	Double
			3: initialize	X	Double
				Z	Double
				Old Diameter	Double	Current length of a single side of the world border, in meters
				New Diameter	Double	Target length of a single side of the world border, in meters
				Speed	VarLong	Number of real-time milliseconds until New Diameter is reached. It appears that Notchian server does not sync world border speed to game ticks, so it gets out of sync with server lag. If the world border is not moving, this is set to 0.
				Portal Teleport Boundary	VarInt	Resulting coordinates from a portal teleport are limited to ±value. Usually 29999984.
				Warning Time	VarInt	In seconds as set by `/worldborder warning time`
				Warning Blocks	VarInt	In meters
			4: set warning time	Warning Time	VarInt	In seconds as set by `/worldborder warning time`
			5: set warning blocks	Warning Blocks	VarInt	In meters

1.9.2

Packet ID	State	Bound To	Field Name		Field Type	Notes
0x35	Play	Client	Action		VarInt Enum	Determines the format of the rest of the packet
			Action	Field Name
			0: set size	Diameter	Double	Length of a single side of the world border, in meters
			1: lerp size	Old Diameter	Double	Current length of a single side of the world border, in meters
				New Diameter	Double	Target length of a single side of the world border, in meters
				Speed	VarLong	Number of real-time milliseconds until New Diameter is reached. It appears that Notchian server does not sync world border speed to game ticks, so it gets out of sync with server lag. If the world border is not moving, this is set to 0.
			2: set center	X	Double
			2: set center	Z	Double
			3: initialize	X	Double
				Z	Double
				Old Diameter	Double	Current length of a single side of the world border, in meters
				New Diameter	Double	Target length of a single side of the world border, in meters
				Speed	VarLong	Number of real-time milliseconds until New Diameter is reached. It appears that Notchian server does not sync world border speed to game ticks, so it gets out of sync with server lag. If the world border is not moving, this is set to 0.
				Portal Teleport Boundary	VarInt	Resulting coordinates from a portal teleport are limited to ±value. Usually 29999984.
				Warning Time	VarInt	In seconds as set by `/worldborder warning time`
				Warning Blocks	VarInt	In meters
			4: set warning time	Warning Time	VarInt	In seconds as set by `/worldborder warning time`
			5: set warning blocks	Warning Blocks	VarInt	In meters

1.9

Packet ID	State	Bound To	Field Name		Field Type	Notes
0x35	Play	Client	Action		VarInt Enum	Determines the format of the rest of the packet
			Action	Field Name
			0: set size	Diameter	Double	Length of a single side of the world border, in meters
			1: lerp size	Old Diameter	Double	Current length of a single side of the world border, in meters
				New Diameter	Double	Target length of a single side of the world border, in meters
				Speed	VarLong	Number of real-time milliseconds until New Diameter is reached. It appears that Notchian server does not sync world border speed to game ticks, so it gets out of sync with server lag. If the world border is not moving, this is set to 0.
			2: set center	X	Double
			2: set center	Z	Double
			3: initialize	X	Double
				Z	Double
				Old Diameter	Double	Current length of a single side of the world border, in meters
				New Diameter	Double	Target length of a single side of the world border, in meters
				Speed	VarLong	Number of real-time milliseconds until New Diameter is reached. It appears that Notchian server does not sync world border speed to game ticks, so it gets out of sync with server lag. If the world border is not moving, this is set to 0.
				Portal Teleport Boundary	VarInt	Resulting coordinates from a portal teleport are limited to ±value. Usually 29999984.
				Warning Time	VarInt	In seconds as set by `/worldborder warning time`
				Warning Blocks	VarInt	In meters
			4: set warning time	Warning Time	VarInt	In seconds as set by `/worldborder warning time`
			5: set warning blocks	Warning Blocks	VarInt	In meters

1.8.X

Packet ID	State	Bound To	Field Name		Field Type	Notes
0x44	Play	Client	Action		VarInt	Determines the format of the rest of the packet
			Action	Field Name
			0: set size	Radius	Double	meters
			1: lerp size	Old Radius	Double	meters
				New Radius	Double	meters
				Speed	VarLong	number of real-time ticks/seconds (?) until New Radius is reached. From experiments, it appears that Notchian server does not sync world border speed to game ticks, so it gets out of sync with server lag
			2: set center	X	Double
			2: set center	Z	Double
			3: initialize	X	Double
				Z	Double
				Old Radius	Double
				New Radius	Double
				Speed	VarLong
				Portal Teleport Boundary	VarInt	Resulting coordinates from a portal teleport are limited to +-value. Usually 29999984.
				Warning Time	VarInt
				Warning Blocks	VarInt
			4: set warning time	Warning Time	VarInt	unit?
			5: set warning blocks	Warning Blocks	VarInt