diff --git a/build/Dockerfile b/build/Dockerfile
index 876d8d79..88c8d4fd 100644
--- a/build/Dockerfile
+++ b/build/Dockerfile
@@ -1,4 +1,4 @@
-FROM mcr.microsoft.com/dotnet/sdk:7.0
+FROM mcr.microsoft.com/dotnet/sdk:9.0
 
 # https://www.nuget.org/packages/dotnet-script/
 RUN dotnet tool install dotnet-script --tool-path /usr/bin