diff --git a/ProtocolLib/dependency-reduced-pom.xml b/ProtocolLib/dependency-reduced-pom.xml
index 4c88f2ae..c69963b3 100644
--- a/ProtocolLib/dependency-reduced-pom.xml
+++ b/ProtocolLib/dependency-reduced-pom.xml
@@ -139,7 +139,7 @@
     <dependency>
       <groupId>org.bukkit</groupId>
       <artifactId>craftbukkit</artifactId>
-      <version>1.4.5-R0.3-SNAPSHOT</version>
+      <version>1.4.6-R0.1</version>
       <scope>provided</scope>
     </dependency>
     <dependency>
@@ -154,6 +154,36 @@
         </exclusion>
       </exclusions>
     </dependency>
+    <dependency>
+      <groupId>org.mockito</groupId>
+      <artifactId>mockito-all</artifactId>
+      <version>1.8.4</version>
+      <scope>test</scope>
+    </dependency>
+    <dependency>
+      <groupId>org.powermock</groupId>
+      <artifactId>powermock-module-junit4</artifactId>
+      <version>1.5</version>
+      <scope>test</scope>
+      <exclusions>
+        <exclusion>
+          <artifactId>powermock-module-junit4-common</artifactId>
+          <groupId>org.powermock</groupId>
+        </exclusion>
+      </exclusions>
+    </dependency>
+    <dependency>
+      <groupId>org.powermock</groupId>
+      <artifactId>powermock-api-mockito</artifactId>
+      <version>1.5</version>
+      <scope>test</scope>
+      <exclusions>
+        <exclusion>
+          <artifactId>powermock-api-support</artifactId>
+          <groupId>org.powermock</groupId>
+        </exclusion>
+      </exclusions>
+    </dependency>
   </dependencies>
   <reporting>
     <plugins>
@@ -181,6 +211,7 @@
     </snapshotRepository>
   </distributionManagement>
   <properties>
+    <powermock.version>1.5</powermock.version>
     <project.build.sourceEncoding>cp1252</project.build.sourceEncoding>
   </properties>
 </project>
diff --git a/ProtocolLib/pom.xml b/ProtocolLib/pom.xml
index 4fa87e38..d1803e54 100644
--- a/ProtocolLib/pom.xml
+++ b/ProtocolLib/pom.xml
@@ -216,6 +216,7 @@
 		<groupId>org.mockito</groupId>
 		<artifactId>mockito-all</artifactId>
 		<version>1.8.4</version>
+		<scope>test</scope>
 	</dependency>
 	<dependency>
     	<groupId>org.powermock</groupId>
diff --git a/ProtocolLib/src/main/java/com/comphenix/protocol/MinecraftVersion.java b/ProtocolLib/src/main/java/com/comphenix/protocol/MinecraftVersion.java
index 6544ac11..963c8430 100644
--- a/ProtocolLib/src/main/java/com/comphenix/protocol/MinecraftVersion.java
+++ b/ProtocolLib/src/main/java/com/comphenix/protocol/MinecraftVersion.java
@@ -7,13 +7,14 @@ import org.bukkit.Server;
 
 import com.google.common.base.Objects;
 import com.google.common.collect.ComparisonChain;
+import com.google.common.collect.Ordering;
 
 /**
  * Determine the current Minecraft version.
  * 
  * @author Kristian
  */
-class MinecraftVersion implements Comparable<MinecraftVersion> {
+public class MinecraftVersion implements Comparable<MinecraftVersion> {
 	/**
 	 * Regular expression used to parse version strings.
 	 */
@@ -22,6 +23,9 @@ class MinecraftVersion implements Comparable<MinecraftVersion> {
 	private final int major;
 	private final int minor;
 	private final int build;
+	
+	// The development stage
+	private final String development;
 
 	/**
 	 * Determine the current Minecraft version.
@@ -36,11 +40,13 @@ class MinecraftVersion implements Comparable<MinecraftVersion> {
 	 * @param versionOnly - the version in text form.
 	 */
 	public MinecraftVersion(String versionOnly) {
-		int[] numbers = parseVersion(versionOnly);
+		String[] section = versionOnly.split("-");
+		int[] numbers = parseVersion(section[0]);
 		
 		this.major = numbers[0];
 		this.minor = numbers[1];
 		this.build = numbers[2];
+		this.development = section.length > 1 ? section[1] : null;
 	}
 	
 	/**
@@ -50,9 +56,21 @@ class MinecraftVersion implements Comparable<MinecraftVersion> {
 	 * @param build - build version number.
 	 */
 	public MinecraftVersion(int major, int minor, int build) {
+		this(major, minor, build, null);
+	}
+	
+	/**
+	 * Construct a version object directly.
+	 * @param major - major version number.
+	 * @param minor - minor version number.
+	 * @param build - build version number.
+	 * @param development - development stage.
+	 */
+	public MinecraftVersion(int major, int minor, int build, String development) {
 		this.major = major;
 		this.minor = minor;
 		this.build = build;
+		this.development = development;
 	}
 
 	private int[] parseVersion(String version) {
@@ -65,7 +83,7 @@ class MinecraftVersion implements Comparable<MinecraftVersion> {
 	
 		// The String 1 or 1.2 is interpreted as 1.0.0 and 1.2.0 respectively.
 		for (int i = 0; i < Math.min(numbers.length, elements.length); i++)
-			numbers[i] = Integer.parseInt(elements[i].trim());	
+			numbers[i] = Integer.parseInt(elements[i].trim());
 		return numbers;
 	}
 	
@@ -93,12 +111,23 @@ class MinecraftVersion implements Comparable<MinecraftVersion> {
 		return build;
 	}
 	
+	/**
+	 * Retrieve the development stage.
+	 * @return Development stage, or NULL if this is a release.
+	 */
+	public String getDevelopmentStage() {
+		return development;
+	}
+	
 	/**
 	 * Retrieve the version String (major.minor.build) only.
 	 * @return A normal version string.
 	 */
 	public String getVersion() {
-		return String.format("%s.%s.%s", major, minor, build);
+		if (development == null)
+			return String.format("%s.%s.%s", major, minor, build);
+		else
+			return String.format("%s.%s.%s-%s", major, minor, build, development);
 	}
 	
 	@Override
@@ -110,6 +139,8 @@ class MinecraftVersion implements Comparable<MinecraftVersion> {
 					compare(major, o.major).
 					compare(minor, o.minor).
 					compare(build, o.build).
+					// No development String means it's a release
+					compare(development, o.development, Ordering.natural().nullsLast()).
 					result();
 	}
 	
@@ -125,7 +156,8 @@ class MinecraftVersion implements Comparable<MinecraftVersion> {
 			
 			return major == other.major && 
 				   minor == other.minor && 
-				   build == other.build;
+				   build == other.build &&
+				   Objects.equal(development, other.development);
 		}
 		
 		return false;
diff --git a/ProtocolLib/src/main/java/com/comphenix/protocol/ProtocolLibrary.java b/ProtocolLib/src/main/java/com/comphenix/protocol/ProtocolLibrary.java
index e82f47ff..c8c3e0a8 100644
--- a/ProtocolLib/src/main/java/com/comphenix/protocol/ProtocolLibrary.java
+++ b/ProtocolLib/src/main/java/com/comphenix/protocol/ProtocolLibrary.java
@@ -17,11 +17,14 @@
 
 package com.comphenix.protocol;
 
+import java.io.File;
 import java.io.IOException;
 import java.util.logging.Handler;
 import java.util.logging.Level;
 import java.util.logging.LogRecord;
 import java.util.logging.Logger;
+import java.util.regex.Matcher;
+import java.util.regex.Pattern;
 
 import org.bukkit.Server;
 import org.bukkit.command.CommandExecutor;
@@ -97,6 +100,9 @@ public class ProtocolLibrary extends JavaPlugin {
 	private CommandProtocol commandProtocol;
 	private CommandPacket commandPacket;
 	
+	// Whether or not disable is not needed
+	private boolean skipDisable;
+	
 	@Override
 	public void onLoad() {
 		// Load configuration
@@ -104,7 +110,6 @@ public class ProtocolLibrary extends JavaPlugin {
 		
 		// Add global parameters
 		DetailedErrorReporter detailedReporter = new DetailedErrorReporter(this);
-		updater = new Updater(this, logger, "protocollib", getFile(), "protocol.info");
 		reporter = detailedReporter;
 		
 		try {
@@ -121,6 +126,12 @@ public class ProtocolLibrary extends JavaPlugin {
 		}
 		
 		try {
+			// Check for other versions
+			checkConflictingVersions();
+			
+			// Set updater
+			updater = new Updater(this, logger, "protocollib", getFile(), "protocol.info");
+			
 			unhookTask = new DelayedSingleTask(this);
 			protocolManager = new PacketFilterManager(getClassLoader(), getServer(), unhookTask, detailedReporter);
 			detailedReporter.addGlobalParameter("manager", protocolManager);
@@ -252,6 +263,45 @@ public class ProtocolLibrary extends JavaPlugin {
 			reporter.reportWarning(this, "Unable to retrieve current Minecraft version.", e);
 		}
 	}
+	
+	private void checkConflictingVersions() {
+		Pattern ourPlugin = Pattern.compile("ProtocolLib-(.*)\\.jar");
+		MinecraftVersion currentVersion = new MinecraftVersion(this.getDescription().getVersion());
+		MinecraftVersion newestVersion = null;
+		
+		try {
+			// Scan the plugin folder for newer versions of ProtocolLib
+			File pluginFolder = new File("plugins/");
+			
+			for (File candidate : pluginFolder.listFiles()) {
+				if (candidate.isFile()) {
+					Matcher match = ourPlugin.matcher(candidate.getName());
+					
+					if (match.matches()) {
+						MinecraftVersion version = new MinecraftVersion(match.group(1));
+
+						if (newestVersion == null || newestVersion.compareTo(version) < 0) {
+							newestVersion = version;
+						}
+					}
+				}
+			}
+
+		} catch (Exception e) {
+			reporter.reportWarning(this, "Unable to detect conflicting plugin versions.", e);
+		}
+		
+		// See if the newest version is actually higher
+		if (newestVersion != null && currentVersion.compareTo(newestVersion) < 0) {
+			// We don't need to set internal classes or instances to NULL - that would break the other loaded plugin
+			skipDisable = true;
+			
+			throw new IllegalStateException(
+					String.format("Detected a newer version of ProtocolLib (%s) in plugin folder than the current (%s). Disabling.", 
+							newestVersion.getVersion(), currentVersion.getVersion())
+			);
+		}
+	}
 		
 	private void registerCommand(String name, CommandExecutor executor) {
 		try {
@@ -331,6 +381,10 @@ public class ProtocolLibrary extends JavaPlugin {
 	
 	@Override
 	public void onDisable() {
+		if (skipDisable) {
+			return;
+		}
+		
 		// Disable compiler
 		if (backgroundCompiler != null) {
 			backgroundCompiler.shutdownAll();