diff --git a/build.sbt b/build.sbt
index f8563aa..56ee474 100644
--- a/build.sbt
+++ b/build.sbt
@@ -10,7 +10,7 @@ organization := "edu.berkeley.cs"
 version := "1.5-SNAPSHOT"
 autoAPIMappings := true
 scalaVersion := "2.12.10"
-crossScalaVersions := Seq("2.12.10", "2.11.12")
+crossScalaVersions := Seq("2.12.10", "2.13.5")
 scalacOptions := Seq("-deprecation", "-feature") ++ scalacOptionsVersion(scalaVersion.value)
 
 def scalacOptionsVersion(scalaVersion: String): Seq[String] = {