Just got this exception maybe because of a corrupted sign text from previous version.
I upgraded to 9.8.3 and got 4x this Nullpointer, seems to works fine anyway.

[09:53:47 INFO]: PreciousStones zones: 2
[09:53:47 INFO]: PreciousStones cuboids: 2506
[09:53:48 INFO]: PreciousStones cuboids: 27
[09:53:48 INFO]: PreciousStones cuboids: 13
[09:53:48 INFO]: PreciousStones cuboids: 12
[09:53:48 WARN]: [PreciousStones] Task #1053 for PreciousStones v9.8.3 generated an exception
java.lang.NullPointerException
at net.sacredlabyrinth.Phaed.PreciousStones.entries.FieldSign.extractData(FieldSign.java:103) ~[?:?]
at net.sacredlabyrinth.Phaed.PreciousStones.entries.FieldSign.(FieldSign.java:37) ~[?:?]
at net.sacredlabyrinth.Phaed.PreciousStones.SignHelper.getAttachedFieldSign(SignHelper.java:72) ~[?:?]
at net.sacredlabyrinth.Phaed.PreciousStones.vectors.Field.getAttachedFieldSign(Field.java:2825) ~[?:?]
at net.sacredlabyrinth.Phaed.PreciousStones.vectors.Field$Update.run(Field.java:3082) ~[?:?]
at org.bukkit.craftbukkit.v1_8_R1.scheduler.CraftTask.run(CraftTask.java:71) ~[spigot.jar:git-Spigot-c3c767f-33d5de3]
at org.bukkit.craftbukkit.v1_8_R1.scheduler.CraftScheduler.mainThreadHeartbeat(CraftScheduler.java:350) [spigot.jar:git-Spigot-c3c767f-33d5de3]
at net.minecraft.server.v1_8_R1.MinecraftServer.z(MinecraftServer.java:709) [spigot.jar:git-Spigot-c3c767f-33d5de3]
at net.minecraft.server.v1_8_R1.DedicatedServer.z(DedicatedServer.java:316) [spigot.jar:git-Spigot-c3c767f-33d5de3]
at net.minecraft.server.v1_8_R1.MinecraftServer.y(MinecraftServer.java:634) [spigot.jar:git-Spigot-c3c767f-33d5de3]
at net.minecraft.server.v1_8_R1.MinecraftServer.run(MinecraftServer.java:537) [spigot.jar:git-Spigot-c3c767f-33d5de3]
at java.lang.Thread.run(Thread.java:745) [?:1.8.0_40]