diff --git a/lakefile.lean b/lakefile.lean
index b9e06d52080043..7e6cc139f51d9e 100644
--- a/lakefile.lean
+++ b/lakefile.lean
@@ -26,7 +26,7 @@ package mathlib where
 meta if get_config? doc = some "on" then -- do not download and build doc-gen4 by default
 require «doc-gen4» from git "https://github.com/leanprover/doc-gen4" @ "main"
 
-require std from git "https://github.com/leanprover/std4" @ "main"
+require std from git "https://github.com/leanprover/std4" @ "adaptation_2973"
 require Qq from git "https://github.com/leanprover-community/quote4" @ "master"
 require aesop from git "https://github.com/leanprover-community/aesop" @ "master"
 require proofwidgets from git "https://github.com/leanprover-community/ProofWidgets4" @ "v0.0.23"
diff --git a/lean-toolchain b/lean-toolchain
index 6f3419889f7477..2dfbd8295af309 100644
--- a/lean-toolchain
+++ b/lean-toolchain
@@ -1 +1 @@
-leanprover/lean4:nightly-2023-12-16
+leanprover/lean4:nightly-2023-12-19