diff --git a/.git-blame-ignore-revs b/.git-blame-ignore-revs
new file mode 100644
index 000000000..f5d9a0719
--- /dev/null
+++ b/.git-blame-ignore-revs
@@ -0,0 +1,2 @@
+# Scala Steward: Reformat with scalafmt 3.8.6
+ea8e30732bee9b9cd1244337420be56fad291542
diff --git a/.scalafmt.conf b/.scalafmt.conf
index 1fc4569a3..b200819c5 100644
--- a/.scalafmt.conf
+++ b/.scalafmt.conf
@@ -1,4 +1,4 @@
-version=3.8.0
+version=3.8.6
 runner.dialect = scala212
 fileOverride {
   "glob:**/scala-2.13*/**" {
diff --git a/algebird-core/src/main/scala/com/twitter/algebird/ExpHist.scala b/algebird-core/src/main/scala/com/twitter/algebird/ExpHist.scala
index 3a1ebfe2a..cd178e791 100644
--- a/algebird-core/src/main/scala/com/twitter/algebird/ExpHist.scala
+++ b/algebird-core/src/main/scala/com/twitter/algebird/ExpHist.scala
@@ -348,7 +348,6 @@ object ExpHist {
      *
      *   - Find the largest j s.t. 2^j <= (s + l) / (1 + l)
      *   - let s' = 2^j(1 + l) - l
-     *
      *   - let diff = (s - s') is the position of s within that group.
      *   - let b = the little-endian binary rep of diff % (2^j - 1)
      *   - let ret = return vector of length j:
diff --git a/algebird-test/src/test/scala/com/twitter/algebird/TupleAggregatorsTest.scala b/algebird-test/src/test/scala/com/twitter/algebird/TupleAggregatorsTest.scala
index e5c780cbd..05ea97788 100644
--- a/algebird-test/src/test/scala/com/twitter/algebird/TupleAggregatorsTest.scala
+++ b/algebird-test/src/test/scala/com/twitter/algebird/TupleAggregatorsTest.scala
@@ -282,24 +282,28 @@ class TupleAggregatorsTest extends AnyWordSpec with Matchers {
     }
 
     "Create an aggregator from a tuple of 16 aggregators" in {
-      val agg: Aggregator[Int, Tuple16[
-        Int,
-        Int,
-        Int,
-        Int,
-        Int,
-        Int,
-        Int,
-        Int,
-        Int,
-        Int,
-        Int,
-        Int,
-        Int,
-        Int,
+      val agg: Aggregator[
         Int,
-        Int
-      ], Tuple16[Int, Int, Int, Int, Int, Int, Int, Int, Int, Int, Int, Int, Int, Int, Int, Int]] = Tuple16(
+        Tuple16[
+          Int,
+          Int,
+          Int,
+          Int,
+          Int,
+          Int,
+          Int,
+          Int,
+          Int,
+          Int,
+          Int,
+          Int,
+          Int,
+          Int,
+          Int,
+          Int
+        ],
+        Tuple16[Int, Int, Int, Int, Int, Int, Int, Int, Int, Int, Int, Int, Int, Int, Int, Int]
+      ] = Tuple16(
         MinAgg,
         MinAgg,
         MinAgg,
@@ -975,24 +979,28 @@ class TupleAggregatorsTest extends AnyWordSpec with Matchers {
     }
 
     "Create an aggregator from a tuple of 16 aggregators" in {
-      val agg: Aggregator[Int, Tuple16[
-        Int,
-        Int,
-        Int,
-        Int,
-        Int,
-        Int,
-        Int,
-        Int,
-        Int,
-        Int,
-        Int,
-        Int,
-        Int,
-        Int,
+      val agg: Aggregator[
         Int,
-        Int
-      ], Tuple16[Int, Int, Int, Int, Int, Int, Int, Int, Int, Int, Int, Int, Int, Int, Int, Int]] =
+        Tuple16[
+          Int,
+          Int,
+          Int,
+          Int,
+          Int,
+          Int,
+          Int,
+          Int,
+          Int,
+          Int,
+          Int,
+          Int,
+          Int,
+          Int,
+          Int,
+          Int
+        ],
+        Tuple16[Int, Int, Int, Int, Int, Int, Int, Int, Int, Int, Int, Int, Int, Int, Int, Int]
+      ] =
         MultiAggregator(
           (
             MinAgg,
diff --git a/algebird-util/src/main/scala/com/twitter/algebird/util/PromiseLinkMonoid.scala b/algebird-util/src/main/scala/com/twitter/algebird/util/PromiseLinkMonoid.scala
index 7be81988f..5c0295bb1 100644
--- a/algebird-util/src/main/scala/com/twitter/algebird/util/PromiseLinkMonoid.scala
+++ b/algebird-util/src/main/scala/com/twitter/algebird/util/PromiseLinkMonoid.scala
@@ -23,7 +23,8 @@ import com.twitter.util.Promise
  * general version of the TunnelMonoid. See the documentation for TunnelMonoid for general motivation. NOTE:
  * the Promise will be fulfilled with the value just before the PromiseLink is calculated.
  */
-class PromiseLinkMonoid[V](monoid: Monoid[V]) extends Monoid[PromiseLink[V]] { // TODo(jcoveney) rename PromiseLink
+class PromiseLinkMonoid[V](monoid: Monoid[V])
+    extends Monoid[PromiseLink[V]] { // TODo(jcoveney) rename PromiseLink
   def zero: PromiseLink[V] = PromiseLink(new Promise, monoid.zero)
 
   def plus(older: PromiseLink[V], newer: PromiseLink[V]): PromiseLink[V] = {