diff --git a/src/main/scala/plugin/Plugin.scala b/src/main/scala/plugin/Plugin.scala
index 48ae955..3c9fe4a 100644
--- a/src/main/scala/plugin/Plugin.scala
+++ b/src/main/scala/plugin/Plugin.scala
@@ -7,7 +7,7 @@
   val pluginId: String
   val pluginName: String
   val description: String
-  val versions: List[Version]
+  val versions: Seq[Version]
 
   def initialize(registry: PluginRegistry): Unit
 
diff --git a/src/main/scala/servlet/AutoUpdateListener.scala b/src/main/scala/servlet/AutoUpdateListener.scala
index 07edf7e..241eafe 100644
--- a/src/main/scala/servlet/AutoUpdateListener.scala
+++ b/src/main/scala/servlet/AutoUpdateListener.scala
@@ -11,43 +11,10 @@
 import util.JDBCUtil._
 import org.eclipse.jgit.api.Git
 import util.Directory
+import util.{Version, Versions}
 import plugin._
 
 object AutoUpdate {
-  
-  /**
-   * Version of GitBucket
-   * 
-   * @param majorVersion the major version
-   * @param minorVersion the minor version
-   */
-  case class Version(majorVersion: Int, minorVersion: Int){
-    
-    private val logger = LoggerFactory.getLogger(classOf[servlet.AutoUpdate.Version])
-    
-    /**
-     * Execute update/MAJOR_MINOR.sql to update schema to this version.
-     * If corresponding SQL file does not exist, this method do nothing.
-     */
-    def update(conn: Connection): Unit = {
-      val sqlPath = s"update/${majorVersion}_${minorVersion}.sql"
-
-      using(Thread.currentThread.getContextClassLoader.getResourceAsStream(sqlPath)){ in =>
-        if(in != null){
-          val sql = IOUtils.toString(in, "UTF-8")
-          using(conn.createStatement()){ stmt =>
-            logger.debug(sqlPath + "=" + sql)
-            stmt.executeUpdate(sql)
-          }
-        }
-      }
-    }
-    
-    /**
-     * MAJOR.MINOR
-     */
-    val versionString = s"${majorVersion}.${minorVersion}"
-  }
 
   /**
    * The history of versions. A head of this sequence is the current BitBucket version.
@@ -55,8 +22,8 @@
   val versions = Seq(
     new Version(2, 8),
     new Version(2, 7) {
-      override def update(conn: Connection): Unit = {
-        super.update(conn)
+      override def update(conn: Connection, cl: ClassLoader): Unit = {
+        super.update(conn, cl)
         conn.select("SELECT * FROM REPOSITORY"){ rs =>
           // Rename attached files directory from /issues to /comments
           val userName = rs.getString("USER_NAME")
@@ -94,8 +61,8 @@
     new Version(2, 5),
     new Version(2, 4),
     new Version(2, 3) {
-      override def update(conn: Connection): Unit = {
-        super.update(conn)
+      override def update(conn: Connection, cl: ClassLoader): Unit = {
+        super.update(conn, cl)
         conn.select("SELECT ACTIVITY_ID, ADDITIONAL_INFO FROM ACTIVITY WHERE ACTIVITY_TYPE='push'"){ rs =>
           val curInfo = rs.getString("ADDITIONAL_INFO")
           val newInfo = curInfo.split("\n").filter(_ matches "^[0-9a-z]{40}:.*").mkString("\n")
@@ -112,13 +79,13 @@
     new Version(2, 2),
     new Version(2, 1),
     new Version(2, 0){
-      override def update(conn: Connection): Unit = {
+      override def update(conn: Connection, cl: ClassLoader): Unit = {
         import eu.medsea.mimeutil.{MimeUtil2, MimeType}
 
         val mimeUtil = new MimeUtil2()
         mimeUtil.registerMimeDetector("eu.medsea.mimeutil.detector.MagicMimeMimeDetector")
 
-        super.update(conn)
+        super.update(conn, cl)
         conn.select("SELECT USER_NAME, REPOSITORY_NAME FROM REPOSITORY"){ rs =>
           defining(Directory.getAttachedDir(rs.getString("USER_NAME"), rs.getString("REPOSITORY_NAME"))){ dir =>
             if(dir.exists && dir.isDirectory){
@@ -146,8 +113,8 @@
     Version(1, 5),
     Version(1, 4),
     new Version(1, 3){
-      override def update(conn: Connection): Unit = {
-        super.update(conn)
+      override def update(conn: Connection, cl: ClassLoader): Unit = {
+        super.update(conn, cl)
         // Fix wiki repository configuration
         conn.select("SELECT USER_NAME, REPOSITORY_NAME FROM REPOSITORY"){ rs =>
           using(Git.open(getWikiRepositoryDir(rs.getString("USER_NAME"), rs.getString("REPOSITORY_NAME")))){ git =>
@@ -214,32 +181,13 @@
     val context = event.getServletContext
     context.setInitParameter("db.url", s"jdbc:h2:${DatabaseHome};MVCC=true")
 
-    // Migration
     defining(getConnection(event.getServletContext)){ conn =>
+      // Migration
       logger.debug("Start schema update")
-      try {
-        defining(getCurrentVersion()){ currentVersion =>
-          if(currentVersion == headVersion){
-            logger.debug("No update")
-          } else if(!versions.contains(currentVersion)){
-            logger.warn(s"Skip migration because ${currentVersion.versionString} is illegal version.")
-          } else {
-            versions.takeWhile(_ != currentVersion).reverse.foreach(_.update(conn))
-            FileUtils.writeStringToFile(versionFile, headVersion.versionString, "UTF-8")
-            logger.debug(s"Updated from ${currentVersion.versionString} to ${headVersion.versionString}")
-          }
-        }
-      } catch {
-        case ex: Throwable => {
-          logger.error("Failed to schema update", ex)
-          ex.printStackTrace()
-          conn.rollback()
-        }
+      Versions.update(conn, headVersion, getCurrentVersion(), versions, Thread.currentThread.getContextClassLoader){ conn =>
+        FileUtils.writeStringToFile(versionFile, headVersion.versionString, "UTF-8")
       }
-      logger.debug("End schema update")
-
       // Load plugins
-
       PluginRegistry.initialize(conn)
     }
 
diff --git a/src/main/scala/util/Version.scala b/src/main/scala/util/Version.scala
index 00d4854..fed74a8 100644
--- a/src/main/scala/util/Version.scala
+++ b/src/main/scala/util/Version.scala
@@ -40,7 +40,7 @@
 
   private val logger = LoggerFactory.getLogger(Versions.getClass)
 
-  def update(conn: Connection, headVersion: Version, currentVersion: Version, versions: List[Version], cl: ClassLoader)
+  def update(conn: Connection, headVersion: Version, currentVersion: Version, versions: Seq[Version], cl: ClassLoader)
             (save: Connection => Unit): Unit = {
     logger.debug("Start schema update")
     try {