diff --git a/postgres-appliance/Dockerfile.build b/postgres-appliance/Dockerfile.build
index 80b57b8bf..74086322d 100644
--- a/postgres-appliance/Dockerfile.build
+++ b/postgres-appliance/Dockerfile.build
@@ -282,8 +282,9 @@ RUN export DEBIAN_FRONTEND=noninteractive \
         && if [ -d /usr/share/postgresql/9.5/contrib/postgis-$POSTGIS_VERSION ]; then \
             cd /usr/share/postgresql/9.5/contrib/postgis-$POSTGIS_VERSION \
             && for f in *.sql *.pl; do \
-                for v in 9.4 9.6 10; do \
-                    if [ -f /usr/share/postgresql/$v/contrib/postgis-$POSTGIS_VERSION/$f ] \
+                if [ -L $f ]; then continue; fi \
+                && for v in $PGOLDVERSIONS; do \
+                    if [ $v != 9.5 ] && [ -f /usr/share/postgresql/$v/contrib/postgis-$POSTGIS_VERSION/$f ] \
                             && [ ! -L /usr/share/postgresql/$v/contrib/postgis-$POSTGIS_VERSION/$f ] \
                             && diff /usr/share/postgresql/$v/contrib/postgis-$POSTGIS_VERSION/$f $f > /dev/null; then \
                         rm /usr/share/postgresql/$v/contrib/postgis-$POSTGIS_VERSION/$f \
@@ -331,8 +332,9 @@ RUN export DEBIAN_FRONTEND=noninteractive \
         && if [ -d /usr/share/postgresql/9.5/extension ]; then \
             cd /usr/share/postgresql/9.5/extension \
             && for f in *.sql *.control; do \
-                for v in 9.3 9.4 9.6 10; do \
-                    if [ -f /usr/share/postgresql/$v/extension/$f ] \
+                if [ -L $f ]; then continue; fi \
+                && for v in $PGOLDVERSIONS; do \
+                    if [ $v != 9.5 ] && [ -f /usr/share/postgresql/$v/extension/$f ] \
                             && [ ! -L /usr/share/postgresql/$v/extension/$f ] \
                             && diff /usr/share/postgresql/$v/extension/$f $f > /dev/null; then \
                         rm /usr/share/postgresql/$v/extension/$f \