diff --git a/tests/05-cqfd_init_custom_image b/tests/05-cqfd_init_custom_image
index ecf2186..a949291 100755
--- a/tests/05-cqfd_init_custom_image
+++ b/tests/05-cqfd_init_custom_image
@@ -25,7 +25,7 @@ EOF
 
 # Test dockerfile
 mkdir -p .cqfd/docker
-echo "FROM ubuntu:20.04" > .cqfd/docker/Dockerfile
+echo "FROM ubuntu:24.04" > .cqfd/docker/Dockerfile
 
 jtest_prepare "docker registry contains NO image named: $custom_image_1"
 if docker inspect "$custom_image_1" &>/dev/null; then
diff --git a/tests/05-cqfd_run_c b/tests/05-cqfd_run_c
index 1928fd1..c9a8d82 100755
--- a/tests/05-cqfd_run_c
+++ b/tests/05-cqfd_run_c
@@ -27,7 +27,7 @@ test_step1() {
 	$cqfd run -c --debug >> $test_run_c_file
 
 	# at the end of this test, $test_run_c_file is populated
-	if ! grep -qw "target \`build'" $test_run_c_file; then
+	if ! grep -qw "target 'build'" $test_run_c_file; then
 		jtest_log fatal "$test_run_c_file not present after test"
 		jtest_result fail
 		rm -f $test_run_c_file
diff --git a/tests/05-cqfd_run_c_flavor b/tests/05-cqfd_run_c_flavor
index c590e0a..bc7d335 100755
--- a/tests/05-cqfd_run_c_flavor
+++ b/tests/05-cqfd_run_c_flavor
@@ -21,7 +21,7 @@ jtest_prepare "build cmd for '$flavor' flavor and concatenate with an additional
 $cqfd -b $flavor run -c --debug >> $test_run_c_file
 
 # at the end of this test, $test_run_c_file is populated
-if ! grep -qw "target \`foo'" $test_run_c_file; then
+if ! grep -qw "target 'foo'" $test_run_c_file; then
 	jtest_log fatal "$test_run_c_file not present after test"
 	jtest_result fail
 	rm -f $test_run_c_file
diff --git a/tests/05-cqfd_run_su_or_sudo_backend b/tests/05-cqfd_run_su_or_sudo_backend
index 01e8980..1e1b5bc 100755
--- a/tests/05-cqfd_run_su_or_sudo_backend
+++ b/tests/05-cqfd_run_su_or_sudo_backend
@@ -28,7 +28,7 @@ $cqfd init && \
 ################################################################################
 # Use another custom Dockerfile with a recent version of su.
 ################################################################################
-echo "FROM ubuntu:20.04" > .cqfd/docker/Dockerfile
+echo "FROM ubuntu:24.04" > .cqfd/docker/Dockerfile
 echo "ENV CQFD_DEBUG=1" >> .cqfd/docker/Dockerfile
 
 ################################################################################
diff --git a/tests/test_data/.cqfd/centos/Dockerfile b/tests/test_data/.cqfd/centos/Dockerfile
index 7e37bef..ae4553e 100644
--- a/tests/test_data/.cqfd/centos/Dockerfile
+++ b/tests/test_data/.cqfd/centos/Dockerfile
@@ -1,2 +1,2 @@
 FROM centos:centos7
-MAINTAINER The CentOS Project <cloud-ops@centos.org>
+LABEL org.opencontainers.image.authors="cloud-ops@centos.org"
diff --git a/tests/test_data/.cqfd/docker/Dockerfile b/tests/test_data/.cqfd/docker/Dockerfile
index c1ac90f..35870a3 100644
--- a/tests/test_data/.cqfd/docker/Dockerfile
+++ b/tests/test_data/.cqfd/docker/Dockerfile
@@ -1,6 +1,6 @@
-FROM ubuntu:14.04
+FROM ubuntu:24.04
 
-ENV DEBIAN_FRONTEND noninteractive
+ENV DEBIAN_FRONTEND=noninteractive
 
 RUN apt-get update && apt-get install -y --no-install-recommends \
 	make \
diff --git a/tests/test_data/.cqfd/docker/Dockerfile.build_context b/tests/test_data/.cqfd/docker/Dockerfile.build_context
index 6d622ee..601cc79 100644
--- a/tests/test_data/.cqfd/docker/Dockerfile.build_context
+++ b/tests/test_data/.cqfd/docker/Dockerfile.build_context
@@ -1,6 +1,6 @@
-FROM ubuntu:14.04
+FROM ubuntu:24.04
 
-ENV DEBIAN_FRONTEND noninteractive
+ENV DEBIAN_FRONTEND=noninteractive
 
 RUN apt-get update && apt-get install -y --no-install-recommends make
 
diff --git a/tests/test_data/.cqfd/docker/Dockerfile.init_extra_env b/tests/test_data/.cqfd/docker/Dockerfile.init_extra_env
index 13808d2..87e074d 100644
--- a/tests/test_data/.cqfd/docker/Dockerfile.init_extra_env
+++ b/tests/test_data/.cqfd/docker/Dockerfile.init_extra_env
@@ -1,6 +1,6 @@
-FROM ubuntu:14.04
+FROM ubuntu:24.04
 
-ENV DEBIAN_FRONTEND noninteractive
+ENV DEBIAN_FRONTEND=noninteractive
 
 RUN apt-get update && apt-get install -y --no-install-recommends make
 
diff --git a/tests/test_data/.cqfd/docker/Dockerfile.missing_dependencies b/tests/test_data/.cqfd/docker/Dockerfile.missing_dependencies
index 05c9d33..5c8e624 100644
--- a/tests/test_data/.cqfd/docker/Dockerfile.missing_dependencies
+++ b/tests/test_data/.cqfd/docker/Dockerfile.missing_dependencies
@@ -1,3 +1,3 @@
-FROM alpine:3.8
+FROM alpine:3.20
 
 RUN apk update && apk upgrade