diff --git a/.github/workflows/actions.yml b/.github/workflows/actions.yml
index 326011109..e74c9a9da 100644
--- a/.github/workflows/actions.yml
+++ b/.github/workflows/actions.yml
@@ -5,15 +5,19 @@ on:
       - main
       - 2.x
   pull_request:
-    branches:
-      - main
-      - 2.x
+
+# cancel older runs of a pull request;
+# this will not cancel anything for normal git pushes
+concurrency:
+  group: cancel-old-pr-runs-${{ github.workflow }}-${{ github.head_ref || github.run_id }}
+  cancel-in-progress: true
+
 jobs:
   test:
     strategy:
       fail-fast: false
       matrix:
-        java-version: [8, 11]
+        java-version: [8, 11, 17]
         scala-binary-version: [2.12, 2.13, 3]
     runs-on: ubuntu-latest
     steps:
diff --git a/.scalafmt.conf b/.scalafmt.conf
new file mode 100644
index 000000000..94752dfaa
--- /dev/null
+++ b/.scalafmt.conf
@@ -0,0 +1,24 @@
+# Newer versions won't work with Java 8!
+version = "3.7.15"
+
+align.openParenCallSite = false
+align.preset = none
+align.stripMargin = true
+
+assumeStandardLibraryStripMargin = true
+
+continuationIndent.callSite = 2
+continuationIndent.defnSite = 4
+
+docstrings.oneline = keep
+docstrings.style = Asterisk
+docstrings.wrap = no
+
+maxColumn = 100
+
+newlines.source = keep
+
+project.git = true
+
+runner.dialect = scala213
+