Server is crashing when equipping the backpack.

Minecraft version : 1.16.2
Forge version : 33.0.21
Mod version : TravelersBackpack-1.16.2-5.1.0.jar

[27Aug2020 12:47:59.734] [Server thread/ERROR] [net.minecraft.server.MinecraftServer/]: Encountered an unexpected exception java.lang.NoSuchMethodError: net.minecraftforge.common.util.LazyOptional.map(Lnet/minecraftforge/common/util/NonNullFunction;)Ljava/util/Optional; at com.tiviacz.travelersbackpack.capability.CapabilityUtils.isWearingBackpack(CapabilityUtils.java:34) ~[?:1.16.2-5.1.0] at com.tiviacz.travelersbackpack.network.EquipBackpackPacket.lambda$handle$0(EquipBackpackPacket.java:40) ~[?:1.16.2-5.1.0] at net.minecraftforge.fml.network.NetworkEvent$Context.enqueueWork(NetworkEvent.java:215) ~[?:?] at com.tiviacz.travelersbackpack.network.EquipBackpackPacket.handle(EquipBackpackPacket.java:35) ~[?:1.16.2-5.1.0] at net.minecraftforge.fml.network.simple.IndexedMessageCodec.lambda$tryDecode$3(IndexedMessageCodec.java:128) ~[?:?] at java.util.Optional.ifPresent(Optional.java:159) ~[?:1.8.0_252] at net.minecraftforge.fml.network.simple.IndexedMessageCodec.tryDecode(IndexedMessageCodec.java:128) ~[?:?] at net.minecraftforge.fml.network.simple.IndexedMessageCodec.consume(IndexedMessageCodec.java:162) ~[?:?] at net.minecraftforge.fml.network.simple.SimpleChannel.networkEventListener(SimpleChannel.java:80) ~[?:?] at net.minecraftforge.eventbus.EventBus.doCastFilter(EventBus.java:247) ~[eventbus-3.0.3-service.jar:?] at net.minecraftforge.eventbus.EventBus.lambda$addListener$11(EventBus.java:239) ~[eventbus-3.0.3-service.jar:?] at net.minecraftforge.eventbus.EventBus.post(EventBus.java:297) ~[eventbus-3.0.3-service.jar:?] at net.minecraftforge.fml.network.NetworkInstance.dispatch(NetworkInstance.java:84) ~[?:?] at net.minecraftforge.fml.network.NetworkHooks.lambda$onCustomPayload$1(NetworkHooks.java:73) ~[?:?] at java.util.Optional.map(Optional.java:215) ~[?:1.8.0_252] at net.minecraftforge.fml.network.NetworkHooks.onCustomPayload(NetworkHooks.java:73) ~[?:?] at net.minecraft.network.play.ServerPlayNetHandler.func_147349_a(ServerPlayNetHandler.java:1326) ~[?:?] at net.minecraft.network.play.client.CCustomPayloadPacket.func_148833_a(CCustomPayloadPacket.java:42) ~[?:?] at net.minecraft.network.play.client.CCustomPayloadPacket.func_148833_a(CCustomPayloadPacket.java:12) ~[?:?] at net.minecraft.network.PacketThreadUtil.func_225383_a(SourceFile:21) ~[?:?] at net.minecraft.util.concurrent.TickDelayedTask.run(SourceFile:18) ~[?:?] at net.minecraft.util.concurrent.ThreadTaskExecutor.func_213166_h(SourceFile:144) ~[?:?] at net.minecraft.util.concurrent.RecursiveEventLoop.func_213166_h(SourceFile:23) ~[?:?] at net.minecraft.server.MinecraftServer.func_213166_h(MinecraftServer.java:729) ~[?:?] at net.minecraft.server.MinecraftServer.func_213166_h(MinecraftServer.java:156) ~[?:?] at net.minecraft.util.concurrent.ThreadTaskExecutor.func_213168_p(SourceFile:118) ~[?:?] at net.minecraft.server.MinecraftServer.func_213205_aW(MinecraftServer.java:712) ~[?:?] at net.minecraft.server.MinecraftServer.func_213168_p(MinecraftServer.java:706) ~[?:?] at net.minecraft.util.concurrent.ThreadTaskExecutor.func_213160_bf(SourceFile:103) ~[?:?] at net.minecraft.server.MinecraftServer.func_213202_o(MinecraftServer.java:691) ~[?:?] at net.minecraft.server.MinecraftServer.func_240802_v_(MinecraftServer.java:641) ~[?:?] at net.minecraft.server.MinecraftServer.lambda$func_240784_a_$0(MinecraftServer.java:229) ~[?:?] at java.lang.Thread.run(Thread.java:748) [?:1.8.0_252]

https://www.curseforge.com/minecraft/mc-mods/travelers-backpack/files/3050208