HELP!

[Server thread/INFO]: [Essentials] Enabling Essentials v2.13.1[2016-03-19 16:05:12,014-0400] [Server thread/INFO]: Bukkit version format changed. Version not checked.[2016-03-19 16:05:12,014-0400] [Server thread/INFO]: git-Spigot-db6de12-07c3001 (MC: 1.8.8)[2016-03-19 16:05:12,014-0400] [Server thread/INFO]: 1.8.8-R0.1-SNAPSHOT[2016-03-19 16:05:12,017-0400] [Server thread/ERROR]: java.lang.NoSuchMethodError:                                                                                       com.google.common.cache.CacheBuilder.maximumSize(Lcom/google/common/cache/Cache Builder;[2016-03-19 16:05:12,018-0400] [Server thread/WARN]: Essentials userMap not initialized[2016-03-19 16:05:12,020-0400] [Server thread/ERROR]: Error occurred while enabling Essentials v2.13.1 (Is it up to date?)java.lang.NullPointerException at com.earth2me.essentials.Essentials.onDisable(Essentials.java:312) ~[?:?]at org.bukkit.plugin.java.JavaPlugin.setEnabled(JavaPlugin.java:323) ~[spigot-1.8.8.jar:git-Spigot-db6de12-07c3001]        at com.earth2me.essentials.Essentials.handleCrash(Essentials.java:702) ~[?:?]at com.earth2me.essentials.Essentials.onEnable(Essentials.java:256) ~[?:?] at org.bukkit.plugin.java.JavaPlugin.setEnabled(JavaPlugin.java:321) ~[spi