diff --git a/.gitlab-ci.yml b/.gitlab-ci.yml
index d313e459955035ae8060592396b518dce415b567..580b05bcdc83cd21c4f0724e119600c8da8f288c 100644
--- a/.gitlab-ci.yml
+++ b/.gitlab-ci.yml
@@ -41,10 +41,11 @@ variables:
 
 ## Build jobs
 
-build-coq.8.15.dev:
+build-coq.8.15.0:
   <<: *template
   variables:
-    OPAM_PINS: "coq version 8.15.dev"
+    OPAM_PINS: "coq version 8.15.0"
+    DENY_WARNINGS: "1"
 
 build-coq.8.14.1:
   <<: *template
diff --git a/README.md b/README.md
index be93cd60a1b4f39b31a97d74c15fdd27f1333f05..2dc2970c9d9f01ccb26dd4b365e52c8f02da1b61 100644
--- a/README.md
+++ b/README.md
@@ -45,7 +45,7 @@ Notably:
 
 This version is known to compile with:
 
- - Coq version 8.11.2 / 8.12.2 / 8.13.2 / 8.14.1
+ - Coq version 8.11.2 / 8.12.2 / 8.13.2 / 8.14.1 / 8.15.0
 
 ## Installing via opam
 
diff --git a/_CoqProject b/_CoqProject
index d6dd2d82030bee165a2f94705f314db6172583af..dc020706b9802fc1033d9a51ce07cdd32742f4f8 100644
--- a/_CoqProject
+++ b/_CoqProject
@@ -3,6 +3,8 @@
 -arg -w -arg -deprecated-hint-rewrite-without-locality
 # Fixing this one requires Coq 8.15.
 -arg -w -arg -deprecated-typeclasses-transparency-without-locality
+# Fixing this one requires Coq 8.13.
+-arg -w -arg -deprecated-syntactic-definition
 
 theories/options.v
 theories/base.v