diff --git a/fsharp/.devcontainer.json b/fsharp/.devcontainer.json
index 0b5cec1a..59d00ceb 100644
--- a/fsharp/.devcontainer.json
+++ b/fsharp/.devcontainer.json
@@ -1,6 +1,6 @@
 {
   "name": "F# Dotnet",
-  "image": "mcr.microsoft.com/devcontainers/dotnet:8.0",
+  "image": "mcr.microsoft.com/devcontainers/dotnet:9.0",
   "onCreateCommand": "dotnet build",
   "customizations": {
     "github.com/rradczewski/kata-bootstraps": {
diff --git a/fsharp/Application/Application.fsproj b/fsharp/Application/Application.fsproj
index 1d00ce01..7cac4ca9 100644
--- a/fsharp/Application/Application.fsproj
+++ b/fsharp/Application/Application.fsproj
@@ -2,7 +2,7 @@
 
   <PropertyGroup>
     <OutputType>Exe</OutputType>
-    <TargetFramework>net8.0</TargetFramework>
+    <TargetFramework>net9.0</TargetFramework>
   </PropertyGroup>
 
   <ItemGroup>
diff --git a/fsharp/Tests/Tests.fsproj b/fsharp/Tests/Tests.fsproj
index fbdf3e41..81b1d33d 100644
--- a/fsharp/Tests/Tests.fsproj
+++ b/fsharp/Tests/Tests.fsproj
@@ -1,7 +1,7 @@
 <Project Sdk="Microsoft.NET.Sdk">
 
   <PropertyGroup>
-    <TargetFramework>net8.0</TargetFramework>
+    <TargetFramework>net9.0</TargetFramework>
 
     <IsPackable>false</IsPackable>
     <GenerateProgramFile>false</GenerateProgramFile>