diff --git a/build.sbt b/build.sbt
index 4819aa0..b35f3c0 100644
--- a/build.sbt
+++ b/build.sbt
@@ -1,4 +1,4 @@
-lazy val scala212 = "2.12.20"
+lazy val scala212 = "2.13.16"
 lazy val scala3 = "3.7.2"
 ThisBuild / crossScalaVersions := Seq(scala212, scala3)
 ThisBuild / scalaVersion := scala212
diff --git a/src/sbt-test/unidoc/java-unidoc/build.sbt b/src/sbt-test/unidoc/java-unidoc/build.sbt
index b380f3c..8d7cf3c 100644
--- a/src/sbt-test/unidoc/java-unidoc/build.sbt
+++ b/src/sbt-test/unidoc/java-unidoc/build.sbt
@@ -1,5 +1,5 @@
 val commonSettings = Seq(
-  scalaVersion := "2.12.20"
+  scalaVersion := "2.13.16"
 )
 
 def module(name: String) =
diff --git a/src/sbt-test/unidoc/scala-unidoc/build.sbt b/src/sbt-test/unidoc/scala-unidoc/build.sbt
index 4577acf..92c6dda 100644
--- a/src/sbt-test/unidoc/scala-unidoc/build.sbt
+++ b/src/sbt-test/unidoc/scala-unidoc/build.sbt
@@ -1,5 +1,5 @@
 val commonSettings = Seq(
-  scalaVersion := "2.12.20"
+  scalaVersion := "2.13.16"
 )
 
 lazy val a = project.settings(