diff --git a/build.sbt b/build.sbt
index 8ac9ac1..edafc58 100644
--- a/build.sbt
+++ b/build.sbt
@@ -1,5 +1,5 @@
 lazy val scala212 = "2.12.18"
-lazy val scala213 = "2.13.7"
+lazy val scala213 = "2.13.12"
 
 lazy val commonSettings = List(
   scalaVersion := scala212,
diff --git a/runtime/src/main/scala/com/soundcloud/twinagle/JsonError.scala b/runtime/src/main/scala/com/soundcloud/twinagle/JsonError.scala
index ace57d0..54ad2dc 100644
--- a/runtime/src/main/scala/com/soundcloud/twinagle/JsonError.scala
+++ b/runtime/src/main/scala/com/soundcloud/twinagle/JsonError.scala
@@ -19,7 +19,7 @@ private[twinagle] object JsonError {
   import org.json4s.native.Serialization.{read, write}
 
   import scala.util.control.Exception._
-  implicit val formats = Serialization.formats(NoTypeHints)
+  implicit val formats: Formats = Serialization.formats(NoTypeHints)
 
   def fromString(str: String): Option[JsonError] = allCatch opt {
     read[JsonError](str)
diff --git a/runtime/src/test/scala/com/soundcloud/twinagle/ClientEndpointBuilderSpec.scala b/runtime/src/test/scala/com/soundcloud/twinagle/ClientEndpointBuilderSpec.scala
index d197050..55d9efb 100644
--- a/runtime/src/test/scala/com/soundcloud/twinagle/ClientEndpointBuilderSpec.scala
+++ b/runtime/src/test/scala/com/soundcloud/twinagle/ClientEndpointBuilderSpec.scala
@@ -5,6 +5,9 @@ import com.twitter.finagle.{Filter, Service}
 import com.twitter.finagle.http.{Request, Response}
 import org.specs2.mutable.Specification
 
+import scala.annotation.nowarn
+
+@nowarn("cat=lint-infer-any")
 class ClientEndpointBuilderSpec extends Specification {
 
   val httpClient: Service[Request, Response] =