diff --git a/build.sbt b/build.sbt
index 5d4e99a..b80a10a 100644
--- a/build.sbt
+++ b/build.sbt
@@ -1,14 +1,14 @@
 organization := "com.chrisomeara"
 name := "pillar-core"
-version := "3.0.0"
-scalaVersion := "2.12.1"
-crossScalaVersions := Seq("2.10.6", "2.11.8", "2.12.1")
+version := "3.0.1"
+scalaVersion := "2.13.1"
 homepage := Some(url("https://github.com/comeara/pillar-core"))
 licenses := Seq("MIT license" -> url("http://www.opensource.org/licenses/mit-license.php"))
 libraryDependencies ++= Seq(
   "com.datastax.cassandra" % "cassandra-driver-core" % "3.0.0",
   "org.mockito" % "mockito-core" % "1.9.5" % "test",
-  "org.scalatest" %% "scalatest" % "3.0.1" % "test",
+  "org.scalatest" %% "scalatest" % "3.1.0" % "test",
+  "org.scalatestplus" %% "scalatestplus-mockito" % "1.0.0-M2" % "test",
   "org.slf4j" % "slf4j-simple" % "1.7.22" % "test"
 )
 publishMavenStyle := true
diff --git a/src/main/scala/com/chrisomeara/pillar/core/AppliedMigrations.scala b/src/main/scala/com/chrisomeara/pillar/core/AppliedMigrations.scala
index 0a56403..41aa45c 100644
--- a/src/main/scala/com/chrisomeara/pillar/core/AppliedMigrations.scala
+++ b/src/main/scala/com/chrisomeara/pillar/core/AppliedMigrations.scala
@@ -5,14 +5,14 @@ import java.util.Date
 import com.datastax.driver.core.Session
 import com.datastax.driver.core.querybuilder.QueryBuilder
 
-import scala.collection.JavaConversions
+import scala.jdk.CollectionConverters._
 
 object AppliedMigrations {
   def apply(session: Session, registry: Registry): AppliedMigrations = {
     val results = session.execute(QueryBuilder.select("authored_at", "description").from("applied_migrations"))
-    new AppliedMigrations(JavaConversions.asScalaBuffer(results.all()).map {
+    new AppliedMigrations(results.all().asScala.map {
       row => registry(MigrationKey(row.getTimestamp("authored_at"), row.getString("description")))
-    })
+    }.toSeq)
   }
 }
 
diff --git a/src/main/scala/com/chrisomeara/pillar/core/Parser.scala b/src/main/scala/com/chrisomeara/pillar/core/Parser.scala
index bc94a50..47bbd23 100644
--- a/src/main/scala/com/chrisomeara/pillar/core/Parser.scala
+++ b/src/main/scala/com/chrisomeara/pillar/core/Parser.scala
@@ -16,23 +16,23 @@ class PartialMigration {
   var description: String = ""
   var authoredAt: String = ""
 
-  var upStages = new mutable.MutableList[String]()
-  var downStages : Option[mutable.MutableList[String]] = None
+  var upStages = new mutable.ArrayDeque[String]()
+  var downStages : Option[mutable.ArrayDeque[String]] = None
 
-  var currentUp = new mutable.MutableList[String]()
-  var currentDown: Option[mutable.MutableList[String]] = None
+  var currentUp = new mutable.ArrayDeque[String]()
+  var currentDown: Option[mutable.ArrayDeque[String]] = None
 
   def rotateUp(): Unit = {
     upStages += currentUp.mkString("\n")
     upStages = upStages.filterNot(line => line.isEmpty)
-    currentUp = new mutable.MutableList[String]()
+    currentUp = new mutable.ArrayDeque[String]()
   }
 
   def rotateDown(): Unit = {
     currentDown match {
       case Some(currentDownLines) =>
         downStages match {
-          case None => downStages = Some(new mutable.MutableList[String]())
+          case None => downStages = Some(new mutable.ArrayDeque[String]())
           case Some(_) =>
         }
 
@@ -95,14 +95,14 @@ class Parser {
         state = ParsingUp
       case MatchAttribute("down", _) =>
         inProgress.rotateUp()
-        inProgress.currentDown = Some(new mutable.MutableList[String]())
+        inProgress.currentDown = Some(new mutable.ArrayDeque[String]())
         state = ParsingDown
       case MatchAttribute("stage", number) =>
         state match {
           case ParsingUp => state = ParsingUpStage
           case ParsingUpStage => inProgress.rotateUp()
           case ParsingDown => state = ParsingDownStage
-          case ParsingDownStage => inProgress.rotateDown(); inProgress.currentDown = Some(new mutable.MutableList[String]())
+          case ParsingDownStage => inProgress.rotateDown(); inProgress.currentDown = Some(new mutable.ArrayDeque[String]())
         }
       case cql =>
         if (!cql.isEmpty) {
@@ -121,11 +121,11 @@ class Parser {
         inProgress.downStages match {
           case Some(downLines) =>
             if (downLines.forall(line => line.isEmpty)) {
-              Migration(inProgress.description, new Date(inProgress.authoredAtAsLong), inProgress.upStages, None)
+              Migration(inProgress.description, new Date(inProgress.authoredAtAsLong), inProgress.upStages.toSeq, None)
             } else {
-              Migration(inProgress.description, new Date(inProgress.authoredAtAsLong), inProgress.upStages, Some(downLines))
+              Migration(inProgress.description, new Date(inProgress.authoredAtAsLong), inProgress.upStages.toSeq, Some(downLines.toSeq))
             }
-          case None => Migration(inProgress.description, new Date(inProgress.authoredAtAsLong), inProgress.upStages)
+          case None => Migration(inProgress.description, new Date(inProgress.authoredAtAsLong), inProgress.upStages.toSeq)
         }
     }
   }
diff --git a/src/test/scala/com/chrisomeara/pillar/core/MigrationSpec.scala b/src/test/scala/com/chrisomeara/pillar/core/MigrationSpec.scala
index a11752b..4388f8a 100644
--- a/src/test/scala/com/chrisomeara/pillar/core/MigrationSpec.scala
+++ b/src/test/scala/com/chrisomeara/pillar/core/MigrationSpec.scala
@@ -3,7 +3,7 @@ package com.chrisomeara.pillar.core
 import java.util.Date
 
 import org.scalatest.{FunSpec, Matchers}
-import org.scalatest.mock.MockitoSugar
+import org.scalatestplus.mockito.MockitoSugar
 
 class MigrationSpec extends FunSpec with Matchers with MockitoSugar {
   describe(".apply") {
diff --git a/src/test/scala/com/chrisomeara/pillar/core/PrintStreamReporterSpec.scala b/src/test/scala/com/chrisomeara/pillar/core/PrintStreamReporterSpec.scala
index 6bbe3d3..7fd53d1 100644
--- a/src/test/scala/com/chrisomeara/pillar/core/PrintStreamReporterSpec.scala
+++ b/src/test/scala/com/chrisomeara/pillar/core/PrintStreamReporterSpec.scala
@@ -5,7 +5,7 @@ import java.util.Date
 
 import com.datastax.driver.core.Session
 import org.scalatest._
-import org.scalatest.mock.MockitoSugar
+import org.scalatestplus.mockito.MockitoSugar
 
 class PrintStreamReporterSpec extends FunSpec with MockitoSugar with Matchers with OneInstancePerTest {
   val session = mock[Session]
diff --git a/src/test/scala/com/chrisomeara/pillar/core/RegistrySpec.scala b/src/test/scala/com/chrisomeara/pillar/core/RegistrySpec.scala
index df6f7b8..44dbb74 100644
--- a/src/test/scala/com/chrisomeara/pillar/core/RegistrySpec.scala
+++ b/src/test/scala/com/chrisomeara/pillar/core/RegistrySpec.scala
@@ -3,7 +3,7 @@ package com.chrisomeara.pillar.core
 import java.io.File
 import java.util.Date
 
-import org.scalatest.mock.MockitoSugar
+import org.scalatestplus.mockito.MockitoSugar
 import org.scalatest.{BeforeAndAfter, FunSpec, Matchers}
 
 class RegistrySpec extends FunSpec with BeforeAndAfter with Matchers with MockitoSugar {
diff --git a/src/test/scala/com/chrisomeara/pillar/core/ReportingMigrationSpec.scala b/src/test/scala/com/chrisomeara/pillar/core/ReportingMigrationSpec.scala
index 91cccf1..5f6ebad 100644
--- a/src/test/scala/com/chrisomeara/pillar/core/ReportingMigrationSpec.scala
+++ b/src/test/scala/com/chrisomeara/pillar/core/ReportingMigrationSpec.scala
@@ -3,7 +3,7 @@ package com.chrisomeara.pillar.core
 import com.datastax.driver.core.Session
 import org.mockito.Mockito._
 import org.scalatest.{FunSpec, Matchers}
-import org.scalatest.mock.MockitoSugar
+import org.scalatestplus.mockito.MockitoSugar
 
 class ReportingMigrationSpec extends FunSpec with Matchers with MockitoSugar {
   val reporter = mock[Reporter]
diff --git a/src/test/scala/com/chrisomeara/pillar/core/ReportingMigratorSpec.scala b/src/test/scala/com/chrisomeara/pillar/core/ReportingMigratorSpec.scala
index 2abd419..9c31dcf 100644
--- a/src/test/scala/com/chrisomeara/pillar/core/ReportingMigratorSpec.scala
+++ b/src/test/scala/com/chrisomeara/pillar/core/ReportingMigratorSpec.scala
@@ -3,7 +3,7 @@ package com.chrisomeara.pillar.core
 import com.datastax.driver.core.Session
 import org.mockito.Mockito._
 import org.scalatest.FunSpec
-import org.scalatest.mock.MockitoSugar
+import org.scalatestplus.mockito.MockitoSugar
 
 class ReportingMigratorSpec extends FunSpec with MockitoSugar {
   val reporter = mock[Reporter]