diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml
index 626fc301..21b0deb8 100644
--- a/.github/workflows/ci.yml
+++ b/.github/workflows/ci.yml
@@ -19,6 +19,7 @@ jobs:
         os: [ 'ubuntu-latest', 'windows-latest' ]
         java: ['8', '17']
         scala: [
+            { version: '2.12.21' },
             { version: '2.12.20' },
             { version: '2.12.19' },
             { version: '2.12.18' },
diff --git a/bin/test-release.sh b/bin/test-release.sh
index c0932257..059b5359 100755
--- a/bin/test-release.sh
+++ b/bin/test-release.sh
@@ -4,11 +4,10 @@ set -eux
 version=$1
 
 coursier fetch \
-  org.scoverage:scalac-scoverage-plugin_2.12.16:$version \
-  org.scoverage:scalac-scoverage-plugin_2.12.17:$version \
   org.scoverage:scalac-scoverage-plugin_2.12.18:$version \
   org.scoverage:scalac-scoverage-plugin_2.12.19:$version \
   org.scoverage:scalac-scoverage-plugin_2.12.20:$version \
+  org.scoverage:scalac-scoverage-plugin_2.12.21:$version \
   org.scoverage:scalac-scoverage-plugin_2.13.11:$version \
   org.scoverage:scalac-scoverage-plugin_2.13.12:$version \
   org.scoverage:scalac-scoverage-plugin_2.13.13:$version \
diff --git a/build.sbt b/build.sbt
index 557c09f0..bb1050ae 100644
--- a/build.sbt
+++ b/build.sbt
@@ -3,15 +3,15 @@ import sbtcrossproject.CrossType
 
 lazy val latestMunitVersion = "1.2.1"
 lazy val scalametaVersion = "4.14.0"
-lazy val defaultScala212 = "2.12.20"
+lazy val defaultScala212 = "2.12.21"
 lazy val defaultScala213 = "2.13.16"
 lazy val defaultScala3 = "3.3.7"
 lazy val bin212 =
   Seq(
     defaultScala212,
+    "2.12.20",
     "2.12.19",
-    "2.12.18",
-    "2.12.17"
+    "2.12.18"
   )
 lazy val bin213 =
   Seq(