diff --git a/project/src/main/scala/Build.scala b/project/src/main/scala/Build.scala
index 1e9eb6ef09..653bc86eb1 100644
--- a/project/src/main/scala/Build.scala
+++ b/project/src/main/scala/Build.scala
@@ -83,7 +83,7 @@ object Build {
     organization := "dev.guardrail",
     licenses += ("MIT", url("http://opensource.org/licenses/MIT")),
 
-    crossScalaVersions := Seq("2.12.18", "2.13.12"),
+    crossScalaVersions := Seq("2.12.18", "2.13.15"),
     scalaVersion := "2.12.18",
 
     // early-semver was a mistake. We already have early-semver guaratees during CI, but including this in the publishing POM