diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml
index b311e9f..aa3343f 100644
--- a/.github/workflows/ci.yml
+++ b/.github/workflows/ci.yml
@@ -48,7 +48,7 @@ jobs:
           local-spark-distrib-tests,
           standalone-tests,
           yarn-spark-distrib-tests,
-          yarn-tests.2_12_11,
+          yarn-tests.2_12_18,
           yarn-tests.2_13_11
         MILL_CHECKS_ORPHAN_SOURCES_IGNORE: >-
           mill-build
diff --git a/build.mill b/build.mill
index be53a63..cdb9c5a 100644
--- a/build.mill
+++ b/build.mill
@@ -32,7 +32,7 @@ implicit def millModuleBasePath: ModuleCtx.Nested =
   )
 
 object Versions {
-  def scala212 = "2.12.11"
+  def scala212 = "2.12.18"
   def scala213 = "2.13.11"
 
   def scala = Seq(scala213, scala212)