diff --git a/coq-lambda-rust.opam b/coq-lambda-rust.opam
index 6f9b966e066ed51ece0a5d4dca4a99606303bff6..bdd09c85ec3fc4e61510c8db286972c395fa03f7 100644
--- a/coq-lambda-rust.opam
+++ b/coq-lambda-rust.opam
@@ -13,7 +13,7 @@ the type system, and safety proof for some Rust libraries.
 """
 
 depends: [
-  "coq-iris" { (= "dev.2023-11-17.0.e29d4cf8") | (= "dev") }
+  "coq-iris" { (= "dev.2023-12-15.0.5fbf777b") | (= "dev") }
 ]
 
 build: [make "-j%{jobs}%"]
diff --git a/theories/lang/heap.v b/theories/lang/heap.v
index de766bd774ba3c5d6e51a1b4d483401152ef05f3..21b6317704e1ae2f7aa3fb7e434eaaea57ff44f1 100644
--- a/theories/lang/heap.v
+++ b/theories/lang/heap.v
@@ -12,6 +12,7 @@ Import uPred.
 Definition lock_stateR : cmra :=
   csumR (exclR unitO) natR.
 
+(* These days this could use gmap_view, but this code predates that. *)
 Definition heapUR : ucmra :=
   gmapUR loc (prodR (prodR fracR lock_stateR) (agreeR valO)).