diff --git a/Manual/BuildTools/Lake/Config.lean b/Manual/BuildTools/Lake/Config.lean
index 61941cfd..cb558f4e 100644
--- a/Manual/BuildTools/Lake/Config.lean
+++ b/Manual/BuildTools/Lake/Config.lean
@@ -180,7 +180,7 @@ name = "example-package"
       licenseFiles := #[FilePath.mk "LICENSE"],
       readmeFile := FilePath.mk "README.md",
       reservoir := true,
-      enableArtifactCache := false},
+      enableArtifactCache? := none},
   configFile := FilePath.mk "lakefile",
   relConfigFile := FilePath.mk "lakefile",
   relManifestFile := FilePath.mk "lake-manifest.json",
@@ -261,7 +261,7 @@ name = "Sorting"
       licenseFiles := #[FilePath.mk "LICENSE"],
       readmeFile := FilePath.mk "README.md",
       reservoir := true,
-      enableArtifactCache := false},
+      enableArtifactCache? := none},
   configFile := FilePath.mk "lakefile",
   relConfigFile := FilePath.mk "lakefile",
   relManifestFile := FilePath.mk "lake-manifest.json",
diff --git a/lean-toolchain b/lean-toolchain
index 8c78ff9c..5c3a6474 100644
--- a/lean-toolchain
+++ b/lean-toolchain
@@ -1 +1 @@
-leanprover/lean4:nightly-2025-06-29
+leanprover/lean4:nightly-2025-06-30