diff --git a/.git-blame-ignore-revs b/.git-blame-ignore-revs
index ee2c14895060..fc23f5f3370e 100644
--- a/.git-blame-ignore-revs
+++ b/.git-blame-ignore-revs
@@ -58,3 +58,6 @@ ceef92f5d6f3d4066564d41b5165351df7cb5fbb
 
 # Format scala code
 4f4257a6de1456f074e946a70dc6464a30858129
+
+# Scala Steward: Reformat with scalafmt 3.8.6
+0f10c64a515ce982bfb52b028f8b8c7e6cc2d128
diff --git a/.scalafmt.conf b/.scalafmt.conf
index d93bc3b74333..d0f7162a5caf 100644
--- a/.scalafmt.conf
+++ b/.scalafmt.conf
@@ -1,4 +1,4 @@
-version = "3.8.5"
+version = "3.8.6"
 
 align.openParenCallSite = false
 align.preset = none
diff --git a/core/api/java11/src/mill/api/JsonFormatters.scala b/core/api/java11/src/mill/api/JsonFormatters.scala
index 97753dd6eba8..18d7e4318351 100644
--- a/core/api/java11/src/mill/api/JsonFormatters.scala
+++ b/core/api/java11/src/mill/api/JsonFormatters.scala
@@ -38,7 +38,7 @@ trait JsonFormatters {
 
   implicit def severityRW: RW[Severity] = JsonFormatters.Default.severityRW
 
-  implicit def resultRW[A: { Reader, Writer }]: RW[Result[A]] = JsonFormatters.Default.resultRW
+  implicit def resultRW[A: {Reader, Writer}]: RW[Result[A]] = JsonFormatters.Default.resultRW
 
   implicit val nioPathRW: RW[java.nio.file.Path] = upickle.readwriter[String]
     .bimap[java.nio.file.Path](
@@ -114,6 +114,6 @@ object JsonFormatters extends JsonFormatters {
     )
 
     given resultFailureExceptionInfoRw: RW[Result.Failure.ExceptionInfo] = RW.derived
-    given resultRW[A: { Reader, Writer }]: RW[Result[A]] = RW.derived
+    given resultRW[A: {Reader, Writer}]: RW[Result[A]] = RW.derived
   }
 }
diff --git a/example/scalalib/linting/5-spotless/.scalafmt.conf b/example/scalalib/linting/5-spotless/.scalafmt.conf
index 5f7d04de25c9..a9175bf7ddff 100644
--- a/example/scalalib/linting/5-spotless/.scalafmt.conf
+++ b/example/scalalib/linting/5-spotless/.scalafmt.conf
@@ -1,2 +1,2 @@
-version = "3.8.5"
+version = "3.8.6"
 runner.dialect = scala213