diff --git a/.github/workflows/check.yml b/.github/workflows/check.yml
index 628c2e9..69370c7 100644
--- a/.github/workflows/check.yml
+++ b/.github/workflows/check.yml
@@ -44,7 +44,7 @@ jobs:
         uses: actions/checkout@v4
         with:
           repository: 'postgres/postgres'
-          ref: 'REL_16_STABLE'
+          ref: 'REL_17_STABLE'
 
       - name: Checkout sources
         uses: actions/checkout@v4
diff --git a/Makefile b/Makefile
index 0711a9e..8005b8a 100644
--- a/Makefile
+++ b/Makefile
@@ -34,7 +34,7 @@ endif
 # Fetches typedefs list for PostgreSQL core and merges it with typedefs defined in this project.
 # https://wiki.postgresql.org/wiki/Running_pgindent_on_non-core_code_or_development_code
 update-typedefs:
-	wget -q -O - "https://buildfarm.postgresql.org/cgi-bin/typedefs.pl?branch=REL_16_STABLE" | cat - typedefs.list | sort | uniq > typedefs-full.list
+	wget -q -O - "https://buildfarm.postgresql.org/cgi-bin/typedefs.pl?branch=REL_17_STABLE" | cat - typedefs.list | sort | uniq > typedefs-full.list
 
 # Indents projects sources.
 indent: