Unknown attribute type "minecraft:health"

[dbaonam99]

21:29:06 [WARNING] Unknown attribute type "minecraft:health"
21:29:06 [WARNING] Unknown attribute type ""
21:29:06 [WARNING] Unknown attribute type ""
21:29:06 [WARNING] Unknown attribute type ""
21:29:06 [WARNING] Unknown attribute type ""
21:29:06 [WARNING] Unknown attribute type ""
21:29:06 [WARNING] Unknown attribute type ""
21:29:06 [ALERT] java.lang.ArrayIndexOutOfBoundsException: 421
at org.itxtech.nemisys.utils.BinaryStream.getByte(BinaryStream.java:202)
at org.itxtech.nemisys.utils.VarInt.read(VarInt.java:50)
at org.itxtech.nemisys.utils.VarInt.readUnsignedVarInt(VarInt.java:95)
at org.itxtech.nemisys.utils.BinaryStream.getUnsignedVarInt(BinaryStream.java:282)
at org.itxtech.nemisys.utils.Binary.readMetadata(Binary.java:452)
at org.itxtech.nemisys.network.protocol.mcpe.AddEntityPacket.decode(AddEntityPacket.java:58)
at org.itxtech.nemisys.Client.handleDataPacket(Client.java:178)
at org.itxtech.nemisys.network.SynapseInterface.handlePacket(SynapseInterface.java:112)
at org.itxtech.nemisys.network.SynapseInterface.processPackets(SynapseInterface.java:83)
at org.itxtech.nemisys.network.SynapseInterface.process(SynapseInterface.java:103)
at org.itxtech.nemisys.Server.tick(Server.java:459)
at org.itxtech.nemisys.Server.tickProcessor(Server.java:426)
at org.itxtech.nemisys.Server.start(Server.java:406)
at org.itxtech.nemisys.Server.(Server.java:202)
at org.itxtech.nemisys.Nemisys.main(Nemisys.java:53)