diff --git a/.gitlab-ci.yml b/.gitlab-ci.yml
index 68463b8def..ab17f9826a 100644
--- a/.gitlab-ci.yml
+++ b/.gitlab-ci.yml
@@ -40,10 +40,10 @@ variables:
   # these tags should be updated each time the list of packages is updated
   # changing these will force rebuilding the associated image
   # Note: these tags have no meaning and are not tied to a particular NM version
-  FEDORA_TAG:  '2020-11-17.0-5276eb5b0e3c'
+  FEDORA_TAG:  '2020-11-17.0-0a04bc0f5618'
   UBUNTU_TAG:  '2020-11-17.0-89dd88de8047'
   DEBIAN_TAG:  '2020-11-17.0-89dd88de8047'
-  CENTOS_TAG:  '2020-11-17.0-5276eb5b0e3c'
+  CENTOS_TAG:  '2020-11-17.0-0a04bc0f5618'
 
   FEDORA_EXEC: 'bash .gitlab-ci/fedora-install.sh'
   UBUNTU_EXEC: 'bash .gitlab-ci/debian-install.sh'
diff --git a/.gitlab-ci/build.sh b/.gitlab-ci/build.sh
index 84beab73ea..fc118b8998 100755
--- a/.gitlab-ci/build.sh
+++ b/.gitlab-ci/build.sh
@@ -16,8 +16,8 @@ locale -a
 env
 meson --version
 
-! which dpkg || dpkg -l
-! which yum  || yum list installed
+! command -v dpkg &>/dev/null || dpkg -l
+! command -v yum  &>/dev/null || yum list installed
 
 # The formatting depends on the version of python black.
 # We have a dedicated test that checks our formatting, which
diff --git a/.gitlab-ci/fedora-install.sh b/.gitlab-ci/fedora-install.sh
index 12f6f73b5f..fe2fd55669 100755
--- a/.gitlab-ci/fedora-install.sh
+++ b/.gitlab-ci/fedora-install.sh
@@ -28,13 +28,13 @@ fi
 
 
 NM_NO_EXTRA=1 NM_INSTALL="yum install -y" ./contrib/fedora/REQUIRED_PACKAGES
-yum install -y glibc-langpack-pl ccache clang which
+yum install -y glibc-langpack-pl ccache clang
 
 # containers have "tsflags=nodocs" in /etc/dnf/dnf.conf. We need /usr/shared/gtk-doc/html
 # to generate proper documentation.
 yum reinstall -y --setopt='tsflags=' glib2-doc
 
-if which dnf &>/dev/null; then
+if command -v dnf &>/dev/null; then
     dnf install -y python3-dnf-plugins-core
     dnf debuginfo-install -y glib2
 else
diff --git a/contrib/fedora/REQUIRED_PACKAGES b/contrib/fedora/REQUIRED_PACKAGES
index 54793c86e0..739433dee9 100755
--- a/contrib/fedora/REQUIRED_PACKAGES
+++ b/contrib/fedora/REQUIRED_PACKAGES
@@ -12,7 +12,7 @@
 
 set -xe
 
-DNF="$( ( which dnf || dnf --version ) &>/dev/null && echo dnf || echo yum)"
+DNF="$(command -v dnf &>/dev/null && echo dnf || echo yum)"
 
 install() {
     if [ "$NM_INSTALL" != "" ]; then
diff --git a/contrib/fedora/rpm/build.sh b/contrib/fedora/rpm/build.sh
index 0e3b82c7e6..abfa42e210 100755
--- a/contrib/fedora/rpm/build.sh
+++ b/contrib/fedora/rpm/build.sh
@@ -255,10 +255,10 @@ ls -dla \
     2>/dev/null | sed 's/^/    /'
 LOG
 if [[ "$BUILDTYPE" == "SRPM" ]]; then
-    LOG sudo $(which dnf &>/dev/null && echo dnf builddep || echo yum-builddep) $TEMP_LATEST/SRPMS/*.src.rpm
+    LOG sudo $(command -v dnf &>/dev/null && echo dnf builddep || echo yum-builddep) $TEMP_LATEST/SRPMS/*.src.rpm
     LOG
 else
-    LOG "sudo $(which dnf &>/dev/null && echo dnf || echo yum) install '$TEMP_LATEST/RPMS'/*/*.rpm"
+    LOG "sudo $(command -v dnf &>/dev/null && echo dnf || echo yum) install '$TEMP_LATEST/RPMS'/*/*.rpm"
     LOG
 fi
 
diff --git a/contrib/scripts/nm-ci-run.sh b/contrib/scripts/nm-ci-run.sh
index 4d46ddb018..10b731c46d 100755
--- a/contrib/scripts/nm-ci-run.sh
+++ b/contrib/scripts/nm-ci-run.sh
@@ -36,7 +36,7 @@ _is_true() {
 }
 
 USE_CCACHE=0
-if which ccache &>/dev/null; then
+if command -v ccache &>/dev/null; then
     USE_CCACHE=1
     export PATH="/usr/lib64/ccache:/usr/lib/ccache${PATH:+:${PATH}}"
 fi
diff --git a/contrib/scripts/nm-code-format-container.sh b/contrib/scripts/nm-code-format-container.sh
index 680c916f21..0be754f57d 100755
--- a/contrib/scripts/nm-code-format-container.sh
+++ b/contrib/scripts/nm-code-format-container.sh
@@ -38,7 +38,7 @@ if ! podman container exists "$PODNAME" ; then
         -v "$DIR:/tmp/NetworkManager:Z" \
         -w /tmp/NetworkManager \
         fedora:33 \
-        /bin/bash -c 'dnf upgrade -y && dnf install -y git which /usr/bin/clang-format && ./contrib/scripts/nm-code-format.sh -i'
+        /bin/bash -c 'dnf upgrade -y && dnf install -y git /usr/bin/clang-format && ./contrib/scripts/nm-code-format.sh -i'
     exit 0
 fi
 
diff --git a/contrib/scripts/nm-code-format.sh b/contrib/scripts/nm-code-format.sh
index c393490b19..3552413bfe 100755
--- a/contrib/scripts/nm-code-format.sh
+++ b/contrib/scripts/nm-code-format.sh
@@ -37,7 +37,7 @@ EXCLUDE=":(exclude)shared/systemd/src
          :(exclude)shared/c-stdaux
          :(exclude)shared/n-acd"
 
-if ! which clang-format &> /dev/null; then
+if ! command -v clang-format &> /dev/null; then
     echo -n "Error: clang-format is not installed, "
     echo "on RHEL/Fedora/CentOS run 'dnf install clang-tools-extra'"
     exit 1
diff --git a/tools/run-nm-test.sh b/tools/run-nm-test.sh
index f452d9d4b8..f8a2bdd584 100755
--- a/tools/run-nm-test.sh
+++ b/tools/run-nm-test.sh
@@ -207,7 +207,7 @@ fi
 
 NMTST_DBUS_RUN_SESSION=()
 if _is_true "$NMTST_LAUNCH_DBUS"; then
-    if ! which dbus-run-session &>/dev/null ; then
+    if ! command -v dbus-run-session &>/dev/null ; then
         eval `dbus-launch --sh-syntax`
         trap "kill $DBUS_SESSION_BUS_PID" EXIT
     else
@@ -249,7 +249,7 @@ if ! _is_true "$NMTST_USE_VALGRIND" 0; then
 fi
 
 if [[ -z "${NMTST_VALGRIND}" ]]; then
-    NMTST_VALGRIND=`which valgrind` || die "cannot find valgrind binary. Set \$NMTST_VALGRIND"
+    NMTST_VALGRIND="$(command -v valgrind)" || die "cannot find valgrind binary. Set \$NMTST_VALGRIND"
 else
     test -e "${NMTST_VALGRIND}" || die "cannot find valgrind binary from NMTST_VALGRIND=\"${NMTST_VALGRIND}\""
 fi