diff --git a/mdoc-sbt/src/sbt-test/sbt-mdoc/basic/project/build.properties b/mdoc-sbt/src/sbt-test/sbt-mdoc/basic/project/build.properties
index 0aa5c39b..49214c4b 100644
--- a/mdoc-sbt/src/sbt-test/sbt-mdoc/basic/project/build.properties
+++ b/mdoc-sbt/src/sbt-test/sbt-mdoc/basic/project/build.properties
@@ -1 +1 @@
-sbt.version = 1.9.8
+sbt.version = 1.9.9
diff --git a/mdoc-sbt/src/sbt-test/sbt-mdoc/extra-arguments/project/build.properties b/mdoc-sbt/src/sbt-test/sbt-mdoc/extra-arguments/project/build.properties
index 0aa5c39b..49214c4b 100644
--- a/mdoc-sbt/src/sbt-test/sbt-mdoc/extra-arguments/project/build.properties
+++ b/mdoc-sbt/src/sbt-test/sbt-mdoc/extra-arguments/project/build.properties
@@ -1 +1 @@
-sbt.version = 1.9.8
+sbt.version = 1.9.9
diff --git a/project/build.properties b/project/build.properties
index abbbce5d..04267b14 100644
--- a/project/build.properties
+++ b/project/build.properties
@@ -1 +1 @@
-sbt.version=1.9.8
+sbt.version=1.9.9