diff --git a/02_basics/project/build.properties b/02_basics/project/build.properties
index 52413ab..04267b1 100644
--- a/02_basics/project/build.properties
+++ b/02_basics/project/build.properties
@@ -1 +1 @@
-sbt.version=1.9.3
+sbt.version=1.9.9
diff --git a/03_domain_modeling/project/build.properties b/03_domain_modeling/project/build.properties
index 52413ab..04267b1 100644
--- a/03_domain_modeling/project/build.properties
+++ b/03_domain_modeling/project/build.properties
@@ -1 +1 @@
-sbt.version=1.9.3
+sbt.version=1.9.9
diff --git a/04_collections/project/build.properties b/04_collections/project/build.properties
index 52413ab..04267b1 100644
--- a/04_collections/project/build.properties
+++ b/04_collections/project/build.properties
@@ -1 +1 @@
-sbt.version=1.9.3
+sbt.version=1.9.9
diff --git a/05_loops/project/build.properties b/05_loops/project/build.properties
index 52413ab..04267b1 100644
--- a/05_loops/project/build.properties
+++ b/05_loops/project/build.properties
@@ -1 +1 @@
-sbt.version=1.9.3
+sbt.version=1.9.9
diff --git a/08_modules/project/build.properties b/08_modules/project/build.properties
index 52413ab..04267b1 100644
--- a/08_modules/project/build.properties
+++ b/08_modules/project/build.properties
@@ -1 +1 @@
-sbt.version=1.9.3
+sbt.version=1.9.9
diff --git a/09_reasoning_about_code/project/build.properties b/09_reasoning_about_code/project/build.properties
index 52413ab..04267b1 100644
--- a/09_reasoning_about_code/project/build.properties
+++ b/09_reasoning_about_code/project/build.properties
@@ -1 +1 @@
-sbt.version=1.9.3
+sbt.version=1.9.9
diff --git a/10_testing/project/build.properties b/10_testing/project/build.properties
index 52413ab..04267b1 100644
--- a/10_testing/project/build.properties
+++ b/10_testing/project/build.properties
@@ -1 +1 @@
-sbt.version=1.9.3
+sbt.version=1.9.9
diff --git a/11_type_directed_programming/project/build.properties b/11_type_directed_programming/project/build.properties
index 52413ab..04267b1 100644
--- a/11_type_directed_programming/project/build.properties
+++ b/11_type_directed_programming/project/build.properties
@@ -1 +1 @@
-sbt.version=1.9.3
+sbt.version=1.9.9
diff --git a/12_extension_methods_and_implicit_conversions/project/build.properties b/12_extension_methods_and_implicit_conversions/project/build.properties
index 52413ab..04267b1 100644
--- a/12_extension_methods_and_implicit_conversions/project/build.properties
+++ b/12_extension_methods_and_implicit_conversions/project/build.properties
@@ -1 +1 @@
-sbt.version=1.9.3
+sbt.version=1.9.9
diff --git a/13_error_handling/project/build.properties b/13_error_handling/project/build.properties
index 52413ab..04267b1 100644
--- a/13_error_handling/project/build.properties
+++ b/13_error_handling/project/build.properties
@@ -1 +1 @@
-sbt.version=1.9.3
+sbt.version=1.9.9
diff --git a/14_asynchronous_programming/project/build.properties b/14_asynchronous_programming/project/build.properties
index 52413ab..04267b1 100644
--- a/14_asynchronous_programming/project/build.properties
+++ b/14_asynchronous_programming/project/build.properties
@@ -1 +1 @@
-sbt.version=1.9.3
+sbt.version=1.9.9
diff --git a/15_phone_mnemonics/project/build.properties b/15_phone_mnemonics/project/build.properties
index 52413ab..04267b1 100644
--- a/15_phone_mnemonics/project/build.properties
+++ b/15_phone_mnemonics/project/build.properties
@@ -1 +1 @@
-sbt.version=1.9.3
+sbt.version=1.9.9
diff --git a/project/build.properties b/project/build.properties
index 52413ab..04267b1 100644
--- a/project/build.properties
+++ b/project/build.properties
@@ -1 +1 @@
-sbt.version=1.9.3
+sbt.version=1.9.9