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 ef3d2662..62499c3d 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 = 1.8.3
+sbt.version = 1.9.1
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 ef3d2662..62499c3d 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 = 1.8.3
+sbt.version = 1.9.1
diff --git a/project/build.properties b/project/build.properties
index 72413de1..3c0b78a7 100644
--- a/project/build.properties
+++ b/project/build.properties
@@ -1 +1 @@
-sbt.version=1.8.3
+sbt.version=1.9.1