diff --git a/_CoqProject b/_CoqProject
index f42ffc03b62a3269624073aca01971cf6db01b45..62de521f99c752660169772c450389a9f2b4ca77 100644
--- a/_CoqProject
+++ b/_CoqProject
@@ -1,5 +1,10 @@
 -Q theories actris
--arg -w -arg -notation-overridden,-redundant-canonical-projection,-several-object-files,-convert_concl_no_check,-undeclared-scope,-ambiguous-paths,-unexpected-implicit-declaration
+# We sometimes want to locally override notation, and there is no good way to do that with scopes.
+-arg -w -arg -notation-overridden
+# Cannot use non-canonical projections as it causes massive unification failures
+# (https://github.com/coq/coq/issues/6294).
+-arg -w -arg -redundant-canonical-projection
+
 theories/utils/skip.v
 theories/utils/llist.v
 theories/utils/compare.v
diff --git a/opam b/opam
index 048f1379046e58c3a331257c12dbc5d8bddc611e..aad382cfae8dd95126d9c1b22bbdfaa9a4b83b4c 100644
--- a/opam
+++ b/opam
@@ -9,5 +9,5 @@ build: [make "-j%{jobs}%"]
 install: [make "install"]
 remove: [ "sh" "-c" "rm -rf '%{lib}%/coq/user-contrib/actris" ]
 depends: [
-  "coq-iris" { (= "dev.2020-07-21.2.e989ad6b") | (= "dev") }
+  "coq-iris" { (= "dev.2020-09-03.1.7dd1b9af") | (= "dev") }
 ]