diff --git a/lake-manifest.json b/lake-manifest.json
index bc54d1b..e334b11 100644
--- a/lake-manifest.json
+++ b/lake-manifest.json
@@ -5,7 +5,7 @@
    "type": "git",
    "subDir": null,
    "scope": "",
-   "rev": "7afce91e4fcee25c1ed06dca8d71b82bed396776",
+   "rev": "470c41643209208d325a5a7315116f293c7443fb",
    "name": "UnicodeBasic",
    "manifestFile": "lake-manifest.json",
    "inputRev": "main",
diff --git a/lean-toolchain b/lean-toolchain
index 4f86f95..cf25a98 100644
--- a/lean-toolchain
+++ b/lean-toolchain
@@ -1 +1 @@
-leanprover/lean4:v4.13.0
+leanprover/lean4:v4.15.0-rc1