The following documentation comment has been logged on the website:
Page: https://www.postgresql.org/docs/13/sql-altercollation.html
Description:
The sample script that is given in section "Notes" finds only libc
collations. If you omit joining "pg_depend" you also find outdated ICU
collations. Like this:
DO $BODY$
DECLARE
r RECORD;
BEGIN
FOR r IN (
SELECT n.nspname, c.collname
FROM pg_collation c JOIN pg_namespace n ON c.collnamespace =
n.oid
WHERE c.collversion <> pg_collation_actual_version(c.oid)
) LOOP
EXECUTE format('ALTER COLLATION %I.%I REFRESH VERSION;', r.nspname,
r.collname);
RAISE NOTICE 'ALTER COLLATION %.% REFRESH VERSION;', r.nspname,
r.collname;
END LOOP;
END;
$BODY$;