diff --git a/.github/workflows/ci.yaml b/.github/workflows/ci.yaml
index abac5d73..3d9997bb 100644
--- a/.github/workflows/ci.yaml
+++ b/.github/workflows/ci.yaml
@@ -50,7 +50,7 @@ jobs:
           - "11"
         scala:
           - "2.12.12"
-          - "2.13.4"
+          - "2.13.6"
   testWithCoverageReport:
     runs-on: ubuntu-latest
     steps:
diff --git a/build.sbt b/build.sbt
index 5bad4b72..3b2630de 100644
--- a/build.sbt
+++ b/build.sbt
@@ -175,7 +175,7 @@ lazy val chill = Project(
 ).settings(sharedSettings)
   .settings(
     name := "chill",
-    crossScalaVersions += "2.13.4",
+    crossScalaVersions += "2.13.6",
     mimaPreviousArtifacts := Set("com.twitter" %% "chill" % binaryCompatVersion),
     mimaBinaryIssueFilters ++= ignoredABIProblems,
     libraryDependencies += "org.apache.xbean" % "xbean-asm7-shaded" % asmVersion
@@ -190,7 +190,7 @@ def akka(scalaVersion: String) =
 
 lazy val chillAkka = module("akka")
   .settings(
-    crossScalaVersions += "2.13.4",
+    crossScalaVersions += "2.13.6",
     resolvers += Resolver.typesafeRepo("releases"),
     libraryDependencies ++= Seq(
       "com.typesafe" % "config" % "1.4.1",
@@ -201,7 +201,7 @@ lazy val chillAkka = module("akka")
 
 lazy val chillBijection = module("bijection")
   .settings(
-    crossScalaVersions += "2.13.4",
+    crossScalaVersions += "2.13.6",
     libraryDependencies ++= Seq(
       "com.twitter" %% "bijection-core" % bijectionVersion
     )
@@ -247,7 +247,7 @@ lazy val chillThrift = module("thrift").settings(
 
 lazy val chillScrooge = module("scrooge")
   .settings(
-    crossScalaVersions += "2.13.4",
+    crossScalaVersions += "2.13.6",
     libraryDependencies ++= Seq(
       ("org.apache.thrift" % "libthrift" % "0.13.0").exclude("junit", "junit"),
       "com.twitter" %% "scrooge-serializer" % scroogeVersion
@@ -277,7 +277,7 @@ lazy val chillAvro = module("avro")
 
 lazy val chillAlgebird = module("algebird")
   .settings(
-    crossScalaVersions += "2.13.4",
+    crossScalaVersions += "2.13.6",
     libraryDependencies ++= Seq(
       "com.twitter" %% "algebird-core" % algebirdVersion
     )
diff --git a/chill-scala/src/test/scala-2.13+/com/twitter/chill/RegistrationIdsSpecData.scala b/chill-scala/src/test/scala-2.13+/com/twitter/chill/RegistrationIdsSpecData.scala
index b5f363b0..2d44f0fb 100644
--- a/chill-scala/src/test/scala-2.13+/com/twitter/chill/RegistrationIdsSpecData.scala
+++ b/chill-scala/src/test/scala-2.13+/com/twitter/chill/RegistrationIdsSpecData.scala
@@ -1,11 +1,11 @@
 /*
-Copyright 2020 Twitter, Inc.
+Copyright 2019 Twitter, Inc.
 
-Licensed under the Apache License, Version 3.1 (the "License");
+Licensed under the Apache License, Version 2.0 (the "License");
 you may not use this file except in compliance with the License.
 You may obtain a copy of the License at
 
-http://www.apache.org/licenses/LICENSE-3.1
+http://www.apache.org/licenses/LICENSE-2.0
 
 Unless required by applicable law or agreed to in writing, software
 distributed under the License is distributed on an "AS IS" BASIS,
diff --git a/chill-scala/src/test/scala-2.13+/com/twitter/chill/SerializedExamplesData.scala b/chill-scala/src/test/scala-2.13+/com/twitter/chill/SerializedExamplesData.scala
index be4d02ca..773c7de4 100644
--- a/chill-scala/src/test/scala-2.13+/com/twitter/chill/SerializedExamplesData.scala
+++ b/chill-scala/src/test/scala-2.13+/com/twitter/chill/SerializedExamplesData.scala
@@ -1,7 +1,7 @@
 /*
-Copyright 2020Twitter, Inc.
+Copyright 2019 Twitter, Inc.
 
-Licensed under the Apache License, Version 2.1(the "License");
+Licensed under the Apache License, Version 2.0 (the "License");
 you may not use this file except in compliance with the License.
 You may obtain a copy of the License at
 
@@ -54,6 +54,7 @@ object SerializedExamplesData {
     16 -> ("EgECBA==" -> Left(2)),
     17 -> ("EwECBA==" -> Right(2)),
     // 18 -> ("FAEBAgQ=" -> Vector(2)),
+    // new vector classes in 2.13 see 144, 145
     19 -> ("FQEBAgQ=" -> Set(2)),
     20 -> ("FgECAgQCBg==" -> Set(2, 3)),
     21 -> ("FwEDAgQCBgII" -> Set(2, 3, 4)),