diff --git a/build.sbt b/build.sbt
index d5ec8e5..bdfd39e 100644
--- a/build.sbt
+++ b/build.sbt
@@ -1,4 +1,4 @@
-ThisBuild / scalaVersion := "2.13.15"
+ThisBuild / scalaVersion := "2.13.16"
 ThisBuild / scalacOptions ++= Seq("-unchecked", "-feature", "-deprecation")
 ThisBuild / libraryDependencies ++= Seq(
   "org.scala-lang" % "scala-reflect" % scalaVersion.value,
diff --git a/laws/src/main/scala/Generator.scala b/laws/src/main/scala/Generator.scala
index 203ded9..66427ae 100644
--- a/laws/src/main/scala/Generator.scala
+++ b/laws/src/main/scala/Generator.scala
@@ -472,12 +472,8 @@ object AllStrLongGenerators {
     val weakHashMap   = register(io.MutKV)(_.weakHashMap())
   }
 
-  object MutKrefV {
-    val anyRefMap     = register(io.MutKrefV)(_.anyRefMap())
-  }
-
   /** This line is needed to actually perform the registration of all generators! */
-  val force = ImmKV :: MutKV :: MutKrefV :: Nil
+  val force = ImmKV :: MutKV :: Nil
 
   lazy val all = everyoneBuffer.result()
 
diff --git a/laws/src/main/scala/Instantiator.scala b/laws/src/main/scala/Instantiator.scala
index ef7acb1..2f7b92f 100644
--- a/laws/src/main/scala/Instantiator.scala
+++ b/laws/src/main/scala/Instantiator.scala
@@ -509,30 +509,6 @@ object InstantiatorsOfStrLong extends InstantiatorsOf[(String, Long)] with Insta
   protected implicit def classTagA: ClassTag[(String, Long)] = ClassTagSource.classTagStringLong
   protected def allFlags = Array[Flag]()
 
-  protected implicit val sizeOfAnyRefMap_String_Long: Sizable[collection.mutable.AnyRefMap[String, Long]] =
-    new Sizable[collection.mutable.AnyRefMap[String, Long]] { 
-      def sizeof(m: collection.mutable.AnyRefMap[String, Long]) = m.size 
-    }
-
-  object MutKrefV extends Instance.PackagePath {
-    // If we have other (String, _) types, move this out into a trait
-    def nickname = "MutKrefV"
-    def fullyQualified = "scala.collection.mutable"
-    def C[CC: TypeTag: Sizable](ccf: Array[(String, Long)] => CC, flags: Flag*)(implicit nm: sourcecode.Name): Deployed[(String, Long), CC] = {
-      val gen = kvInst.makeWith(ccf, (MAP +: flags): _*)(nm, implicitly[TypeTag[CC]], implicitly[Sizable[CC]])
-      val ans = new Deployed[(String, Long), CC]{
-        val secretly = gen
-        var accesses: Int = 0
-        val name = nm.value.toString
-        def group = typeTagA.tpe.toString + " in " + nickname
-        def apply(): Instance.FromArray[(String, Long), CC] = { accesses += 1; secretly }
-      }
-      registry += ans
-      ans
-    }
-    val anyRefMap = C({ a => val m = new collection.mutable.AnyRefMap[String, Long]; for (kv <- a) m += kv; m }, SPECTYPE)
-  }
-
   lazy val possible_a = Array("wish" -> 3L)
   lazy val possible_x = Array(
     Array.empty[(String, Long)],
@@ -547,5 +523,5 @@ object InstantiatorsOfStrLong extends InstantiatorsOf[(String, Long)] with Insta
     *
     * In particular, notice that we're only taking the key-value instantiators, so we only register maps, not all collections.
     */
-  val force = ImmKV :: MutKV :: MutKrefV :: Nil
+  val force = ImmKV :: MutKV :: Nil
 }
diff --git a/laws/src/main/scala/Runner.scala b/laws/src/main/scala/Runner.scala
index 212d0fd..5712c63 100644
--- a/laws/src/main/scala/Runner.scala
+++ b/laws/src/main/scala/Runner.scala
@@ -164,7 +164,7 @@ trait AllRunner {
     import scala.concurrent.duration._
     import scala.concurrent.ExecutionContext.Implicits.global   // Maybe make a fixed-size thread pool?
     val toRun = runners.map(_())
-    val ans = collection.mutable.AnyRefMap.empty[String, Test.Tested]
+    val ans = collection.mutable.Map.empty[String, Test.Tested]
     val slots = new Array[(String, Future[(String, Test.Tested)])](1 max (atOnce min toRun.length))
     var i = 0;
     var it = toRun.iterator