diff --git a/config.json b/config.json
index aca0e706..51afa5fc 100644
--- a/config.json
+++ b/config.json
@@ -412,6 +412,12 @@
       "slug": "parallel-letter-frequency",
       "difficulty": 1,
       "topics": [
+        "Maps",
+        "Sequences",
+        "Strings",
+        "Parallellism",
+        "Transforming",
+        "Dictionaries"
       ]
 		},
     {
diff --git a/exercises/parallel-letter-frequency/build.sbt b/exercises/parallel-letter-frequency/build.sbt
index 5a392603..d023118a 100644
--- a/exercises/parallel-letter-frequency/build.sbt
+++ b/exercises/parallel-letter-frequency/build.sbt
@@ -1,3 +1,3 @@
-scalaVersion := "2.11.7"
+scalaVersion := "2.12.1"
 
-libraryDependencies += "org.scalatest" % "scalatest_2.11" % "2.2.5" % "test"
+libraryDependencies += "org.scalatest" %% "scalatest" % "3.0.1" % "test"
diff --git a/exercises/parallel-letter-frequency/src/main/scala/.keep b/exercises/parallel-letter-frequency/src/main/scala/.keep
deleted file mode 100644
index e69de29b..00000000
diff --git a/exercises/parallel-letter-frequency/src/main/scala/Frequency.scala b/exercises/parallel-letter-frequency/src/main/scala/Frequency.scala
new file mode 100644
index 00000000..b28ec92b
--- /dev/null
+++ b/exercises/parallel-letter-frequency/src/main/scala/Frequency.scala
@@ -0,0 +1,3 @@
+object Frequency {
+  def frequency(numWorkers: Int, texts: Seq[String]): Map[Char, Int] = ???
+}