diff --git a/CHANGES b/CHANGES
index c913700..c1a7c6c 100644
--- a/CHANGES
+++ b/CHANGES
@@ -30,6 +30,9 @@ Corrections:
 	multiple times.
 	Test: MULTIPLE_EOF
 
+	Newer parts of test.sh used substitutions ${x,,*} or ${x^^*} that are
+	not implemented in older bash versions.
+
 ####################### V 1.7.3.3:
 
 Corrections:
diff --git a/test.sh b/test.sh
index 4fa2af9..f2c4473 100755
--- a/test.sh
+++ b/test.sh
@@ -67,6 +67,7 @@ export SOCAT_OPTS="$opts"
 #debug="1"
 debug=
 TESTS="$@"; export TESTS
+
 # for some tests we need a network interface
 if type ip >/dev/null 2>&1; then
     INTERFACE=$(ip r get 8.8.8.8 |grep ' dev ' |head -n 1 |sed "s/.*dev[[:space:]][[:space:]]*\([^[:space:]][^[:space:]]*\).*/\1/")
@@ -148,6 +149,20 @@ rm -f testsrv6.{crt,key,pem}
 CAT=cat
 OD_C="od -c"
 
+toupper () {
+    case ${BASH_VERSION:0:1} in
+	[1-3]) echo "$@" |tr a-z A-Z ;;
+	[4-9]) echo "${@^^*}" ;;
+    esac
+}
+
+tolower () {
+    case ${BASH_VERSION:0:1} in
+	[1-3]) echo "$@" |tr A-Z a-z ;;
+	[4-9]) echo "${@,,*}" ;;
+    esac
+}
+
 # precision sleep; takes seconds with fractional part
 psleep () {
     local T="$1"
@@ -215,7 +230,7 @@ else
     SUBSTUSER="$(grep -v '^[^:]*:^[^:]*:0:' /etc/passwd |tail -n 1 |cut -d: -f1)"
 fi
 
-if type ip >/dev/null; then
+if type ip >/dev/null 2>&1; then
     if ip -V |grep -q "^ip utility, iproute2-ss"; then
 	IP=$(which ip)
     else
@@ -223,7 +238,7 @@ if type ip >/dev/null; then
     fi
 fi
 
-if type ss >/dev/null; then
+if type ss >/dev/null 2>&1; then
     if ss -V |grep -q "^ss utility, iproute2-ss"; then
 	SS=$(which ss)
     else
@@ -11393,7 +11408,7 @@ N=$((N+1))
 
 while read KEYW FEAT ADDR IPPORT; do
 if [ -z "$KEYW" ]|| [[ "$KEYW" == \#* ]]; then continue; fi
-RUNS=${KEYW,,*}
+RUNS=$(tolower $KEYW)
 PROTO=$KEYW
 proto="$(echo "$PROTO" |tr A-Z a-z)"
 # test the max-children option on really connection oriented sockets
@@ -11410,7 +11425,7 @@ elif ! testaddrs "$FEAT" >/dev/null; then
     $PRINTF "test $F_n $TEST... ${YELLOW}$FEAT not available${NORMAL}\n" $N
     numCANT=$((numCANT+1))
 elif ! runs$RUNS >/dev/null; then
-    $PRINTF "test $F_n $TEST... ${YELLOW}${RUNS^^*} not available${NORMAL}\n" $N
+    $PRINTF "test $F_n $TEST... ${YELLOW}$(toupper $RUNS) not available${NORMAL}\n" $N
     numCANT=$((numCANT+1))
 else
 case "X$IPPORT" in
@@ -11475,7 +11490,7 @@ UNIX  unix  $td/test\$N.server -
 
 while read KEYW FEAT ADDR IPPORT SHUT; do
 if [ -z "$KEYW" ]|| [[ "$KEYW" == \#* ]]; then continue; fi
-RUNS=${KEYW,,*}
+RUNS=$(tolower $KEYW)
 PROTO=$KEYW
 proto="$(echo "$PROTO" |tr A-Z a-z)"
 # test the max-children option on pseudo connected sockets
@@ -11493,7 +11508,7 @@ elif ! testaddrs "$FEAT" >/dev/null; then
     $PRINTF "test $F_n $TEST... ${YELLOW}$FEAT not available${NORMAL}\n" $N
     numCANT=$((numCANT+1))
 elif ! runs$RUNS >/dev/null; then
-    $PRINTF "test $F_n $TEST... ${YELLOW}${RUNS^^*} not available${NORMAL}\n" $N
+    $PRINTF "test $F_n $TEST... ${YELLOW}$(toupper $RUNS) not available${NORMAL}\n" $N
     numCANT=$((numCANT+1))
 else
 case "X$IPPORT" in
@@ -11877,7 +11892,7 @@ N=$((N+1))
 while read ssldist MODE MODULE FIELD TESTADDRESS PEERADDRESS VALUE; do
 if [ -z "$ssldist" ] || [[ "$ssldist" == \#* ]]; then continue; fi
 #
-SSLDIST=${ssldist^^*}
+SSLDIST=$(toupper $ssldist)
 NAME="ENV_${SSLDIST}_${MODE}_${MODULE}_${FIELD}"
 case "$TESTS" in
 *%$N%*|*%functions%*|*%ip4%*|*%ipapp%*|*%tcp%*|*%$ssldist%*|*%envvar%*|*%$NAME%*)
@@ -11974,9 +11989,9 @@ while read addr fileopt addropts proto diropt ADDR2; do
 if [ -z "$addr" ] || [[ "$addr" == \#* ]]; then continue; fi
 # some passive (listening...) filesystem based addresses did not implement the
 # umask option
-ADDR=${addr^^*}
+ADDR=$(toupper $addr)
 ADDR_=${ADDR/-/_}
-PROTO=${proto^^*}
+PROTO=$(toupper $proto)
 if [ "$diropt" = "." ]; then diropt=; fi
 if [ "$fileopt" = "." ]; then fileopt=; fi
 if [ "$addropts" = "." ]; then addropts=; fi
@@ -12047,9 +12062,9 @@ pipe          .       .        file     -u       FILE:/dev/null
 while read addr fileopt addropts proto diropt; do
 if [ -z "$addr" ] || [[ "$addr" == \#* ]]; then continue; fi
 # test if passive (listening...) filesystem based addresses implement option perm
-ADDR=${addr^^*}
+ADDR=$(toupper $addr)
 ADDR_=${ADDR/-/_}
-PROTO=${proto^^*}
+PROTO=$(toupper $proto)
 if [ "$diropt" = "." ]; then diropt=; fi
 if [ "$fileopt" = "." ]; then fileopt=; fi
 if [ "$addropts" = "." ]; then addropts=; fi
@@ -12119,9 +12134,9 @@ pty           link    .        file     .
 while read addr fileopt addropts proto diropt; do
 if [ -z "$addr" ] || [[ "$addr" == \#* ]]; then continue; fi
 # test if passive (listening...) filesystem based addresses implement option user
-ADDR=${addr^^*}
+ADDR=$(toupper $addr)
 ADDR_=${ADDR/-/_}
-PROTO=${proto^^*}
+PROTO=$(toupper $proto)
 if [ "$diropt" = "." ]; then diropt=; fi
 if [ "$fileopt" = "." ]; then fileopt=; fi
 if [ "$addropts" = "." ]; then addropts=; fi
@@ -12196,9 +12211,9 @@ while read addr fileopt addropts proto diropt crit ADDR2; do
 if [ -z "$addr" ] || [[ "$addr" == \#* ]]; then continue; fi
 # some passive (listening...) filesystem based addresses did not remove the file
 # system entry at the end
-ADDR=${addr^^*}
+ADDR=$(toupper $addr)
 ADDR_=${ADDR/-/_}
-PROTO=${proto^^*}
+PROTO=$(toupper $proto)
 if [ "$diropt" = "." ]; then diropt=; fi
 if [ "$fileopt" = "." ]; then fileopt=; fi
 if [ "$addropts" = "." ]; then addropts=; fi
@@ -12264,9 +12279,9 @@ while read addr fileopt addropts proto diropt crit ADDR2; do
 if [ -z "$addr" ] || [[ "$addr" == \#* ]]; then continue; fi
 # some passive (listening...) filesystem based addresses with fork did not remove
 # the file system entry at the end
-ADDR=${addr^^*}
+ADDR=$(toupper $addr)
 ADDR_=${ADDR/-/_}
-PROTO=${proto^^*}
+PROTO=$(toupper $proto)
 if [ "$diropt" = "." ]; then diropt=; fi
 if [ "$fileopt" = "." ]; then fileopt=; fi
 if [ "$addropts" = "." ]; then addropts=; fi