diff --git a/src/bin/pg_upgrade/test.sh b/src/bin/pg_upgrade/test.sh
index 8593488907..f353e565b5 100644
--- a/src/bin/pg_upgrade/test.sh
+++ b/src/bin/pg_upgrade/test.sh
@@ -181,53 +181,11 @@ if "$MAKE" -C "$oldsrc" installcheck-parallel; then
 	# Before dumping, tweak the database of the old instance depending
 	# on its version.
 	if [ "$newsrc" != "$oldsrc" ]; then
-		fix_sql=""
-		# Get rid of objects not feasible in later versions
-		case $oldpgversion in
-			804??)
-				fix_sql="DROP FUNCTION public.myfunc(integer);"
-				;;
-		esac
-
-		# Last appeared in v9.6
-		if [ $oldpgversion -lt 100000 ]; then
-			fix_sql="$fix_sql
-					 DROP FUNCTION IF EXISTS
-						public.oldstyle_length(integer, text);"
-		fi
-		# Last appeared in v13
-		if [ $oldpgversion -lt 140000 ]; then
-			fix_sql="$fix_sql
-				 DROP FUNCTION IF EXISTS
-					public.putenv(text);	-- last in v13
-				 DROP OPERATOR IF EXISTS	-- last in v13
-					public.#@# (pg_catalog.int8, NONE),
-					public.#%# (pg_catalog.int8, NONE),
-					public.!=- (pg_catalog.int8, NONE),
-					public.#@%# (pg_catalog.int8, NONE);"
-		fi
-		psql -X -d regression -c "$fix_sql;" || psql_fix_sql_status=$?
-
-		# WITH OIDS is not supported anymore in v12, so remove support
-		# for any relations marked as such.
-		if [ $oldpgversion -lt 120000 ]; then
-			fix_sql="DO \$stmt\$
-				DECLARE
-					rec text;
-				BEGIN
-				FOR rec in
-					SELECT oid::regclass::text
-					FROM pg_class
-					WHERE relname !~ '^pg_'
-						AND relhasoids
-						AND relkind in ('r','m')
-					ORDER BY 1
-				LOOP
-					execute 'ALTER TABLE ' || rec || ' SET WITHOUT OIDS';
-				END LOOP;
-				END; \$stmt\$;"
-			psql -X -d regression -c "$fix_sql;" || psql_fix_sql_status=$?
-		fi
+		# This SQL script has its own idea of the cleanup that needs to be
+		# done on the cluster to-be-upgraded, and includes version checks.
+		# Note that this uses the script stored on the new branch.
+		psql -X -d regression -f "$newsrc/src/bin/pg_upgrade/upgrade_adapt.sql" \
+			|| psql_fix_sql_status=$?
 
 		# Handling of --extra-float-digits gets messy after v12.
 		# Note that this changes the dumps from the old and new
diff --git a/src/bin/pg_upgrade/upgrade_adapt.sql b/src/bin/pg_upgrade/upgrade_adapt.sql
new file mode 100644
index 0000000000..27c4c7fd01
--- /dev/null
+++ b/src/bin/pg_upgrade/upgrade_adapt.sql
@@ -0,0 +1,91 @@
+--
+-- SQL queries for upgrade tests across different major versions.
+--
+-- This file includes a set of SQL queries to make a cluster to-be-upgraded
+-- compatible with the version this file is based on.  Note that this
+-- requires psql, as per-version queries are controlled with a set of \if
+-- clauses.
+
+-- This script is backward-compatible, so it is able to work with any version
+-- newer than 9.2 we are upgrading from, up to the branch this script is stored
+-- on (even if this would not run if running pg_upgrade with the same version
+-- for the origin and the target).
+
+-- \if accepts a simple boolean value, so all the version checks are
+-- saved based on this assumption.
+SELECT
+  ver <= 902 AS oldpgversion_le92,
+  ver <= 904 AS oldpgversion_le94,
+  ver <= 906 AS oldpgversion_le96,
+  ver <= 1000 AS oldpgversion_le10,
+  ver <= 1100 AS oldpgversion_le11,
+  ver <= 1300 AS oldpgversion_le13
+  FROM (SELECT current_setting('server_version_num')::int / 100 AS ver) AS v;
+\gset
+
+-- Objects last appearing in 9.2.
+\if :oldpgversion_le92
+-- Note that those tables are removed from the regression tests in 9.3
+-- and newer versions.
+DROP TABLE abstime_tbl;
+DROP TABLE reltime_tbl;
+DROP TABLE tinterval_tbl;
+\endif
+
+-- Objects last appearing in 9.4.
+\if :oldpgversion_le94
+-- This aggregate has been fixed in 9.5 and later versions, so drop
+-- and re-create it.
+DROP AGGREGATE array_cat_accum(anyarray);
+CREATE AGGREGATE array_larger_accum (anyarray) (
+                  sfunc = array_larger,
+                  stype = anyarray,
+                  initcond = $${}$$);
+-- This operator has been fixed in 9.5 and later versions, so drop and
+-- re-create it.
+DROP OPERATOR @#@ (NONE, bigint);
+CREATE OPERATOR @#@ (PROCEDURE = factorial,
+                     RIGHTARG = bigint);
+\endif
+
+-- Objects last appearing in 9.6.
+\if :oldpgversion_le96
+DROP FUNCTION public.oldstyle_length(integer, text);
+\endif
+
+-- Objects last appearing in 10.
+\if :oldpgversion_le10
+DROP FUNCTION IF EXISTS boxarea(box);
+DROP FUNCTION IF EXISTS funny_dup17();
+\endif
+
+-- Objects last appearing in 11.
+\if :oldpgversion_le11
+-- WITH OIDS is supported until v11, so remove its support for any
+-- relations marked as such.
+DO $stmt$
+  DECLARE
+    rec text;
+  BEGIN
+  FOR rec in
+    SELECT oid::regclass::text
+    FROM pg_class
+    WHERE relname !~ '^pg_'
+      AND relhasoids
+      AND relkind in ('r','m')
+    ORDER BY 1
+  LOOP
+    execute 'ALTER TABLE ' || rec || ' SET WITHOUT OIDS';
+  END LOOP;
+  END; $stmt$;
+\endif
+
+-- Objects last appearing in 13.
+\if :oldpgversion_le13
+-- Until v10, operators could only be dropped one at a time, so be careful
+-- to stick with one command for each drop here.
+DROP OPERATOR public.#@# (pg_catalog.int8, NONE);
+DROP OPERATOR public.#%# (pg_catalog.int8, NONE);
+DROP OPERATOR public.!=- (pg_catalog.int8, NONE);
+DROP OPERATOR public.#@%# (pg_catalog.int8, NONE);
+\endif