diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml
index 78d4ae7d..b8906ada 100644
--- a/.github/workflows/ci.yml
+++ b/.github/workflows/ci.yml
@@ -20,6 +20,7 @@ jobs:
         stack:
           - scalingo-22
           - scalingo-24
+          - scalingo-26
     container:
       image: "scalingo/${{ matrix.stack }}:latest"
       env:
diff --git a/Makefile b/Makefile
index 4e27bdaa..303d2ca5 100644
--- a/Makefile
+++ b/Makefile
@@ -4,12 +4,13 @@ BASH_COMMAND := /bin/bash
 .DEFAULT := all
 
 all: test
-test: test22 test24
+test: test22 test24 test26
 
 test24: STACK := "scalingo-24"
+test26: STACK := "scalingo-26"
 
-test22 test24: BASH_COMMAND := test/run
-test22 test24: IMAGE := "scalingo/$(STACK):latest"
-test22 test24:
+test22 test24 test26: BASH_COMMAND := test/run
+test22 test24 test26: IMAGE := "scalingo/$(STACK):latest"
+test22 test24 test26:
 	@echo "Running tests in Docker using $(IMAGE)"
 	@docker run --pull always --mount type=bind,src=$(PWD),dst=/buildpack,readonly --workdir /buildpack --rm --interactive --tty --env "GITLAB_TOKEN=$(GITLAB_TOKEN)" --env "GITHUB_TOKEN=$(GITHUB_TOKEN)" --env "STACK=$(STACK)" $(IMAGE) bash -c "$(BASH_COMMAND)"
diff --git a/conf/versions.sh b/conf/versions.sh
index 73e3c028..76af3430 100644
--- a/conf/versions.sh
+++ b/conf/versions.sh
@@ -34,7 +34,7 @@ librabbitmq_version="0.15.0"
 
 memcached_version="3.4.0"
 gmp_version="6.3.0"
-tidy_version="5.8.0"
+libtidy_version="5.8.0"
 sodium_version="1.0.22"
 webp_version="${webp_version:-1.6.0}" # Can be found here: https://storage.googleapis.com/downloads.webmproject.org/releases/webp/index.html
 # From https://zlib.net/
@@ -46,7 +46,7 @@ mongodb_version="1.21.5"
 amqp_version="2.2.0"
 phpredis_version="6.3.0"
 apcu_version="5.1.28"
-newrelic_version="12.5.0.30"
+newrelic_version="12.7.0.36"
 
 
 # Legacy support
diff --git a/lib/composer b/lib/composer
index b3b9faf5..173d1448 100644
--- a/lib/composer
+++ b/lib/composer
@@ -154,7 +154,7 @@ function install_composer_deps() {
             elif [ "$ext" = "gmp" ] ; then
               fetch_package "$PHP_BASE_URL" "gmp-${gmp_version}" "/app/vendor/gmp" | indent
             elif [ "$ext" = "tidy" ] ; then
-              fetch_package "$PHP_BASE_URL" "libtidy-${tidy_version}" "/app/vendor/libtidy" | indent
+              fetch_package "$PHP_BASE_URL" "libtidy-${libtidy_version}" "/app/vendor/libtidy" | indent
             elif [ "$ext" = "sodium" ] ; then
               if [[ "$(php_api_version)" -lt "${PHP_MODULE_API_VERSIONS["7.4"]}" ]] ; then
                 sodium_version=$sodium_php72_php73_version
diff --git a/support/ext-internal/tidy b/support/ext-internal/tidy
index 4aeddc7e..e68c9aa2 100755
--- a/support/ext-internal/tidy
+++ b/support/ext-internal/tidy
@@ -1,9 +1,12 @@
 #!/bin/bash
+#
+# Compile the Tidy PHP extension (https://www.php.net/manual/en/book.tidy.php). The outcome is a .so file that is uploaded to the object storage. This file is downloaded during the deployment if a customer enables the Tidy extension.
+#
 
 set -e
 
 if [ -n "$DEBUG" ]; then
-    set -x
+  set -x
 fi
 
 php_version=$1
@@ -11,12 +14,12 @@ zend_api_version=$2
 php_src_dir=$3
 
 source "/buildpack/conf/versions.sh"
-tidy_package="${PHP_BASE_URL}/package/libtidy-${tidy_version}.tgz"
+tidy_package="${PHP_BASE_URL}/package/libtidy-${libtidy_version}.tgz"
 
-curl -L "$tidy_package" > /tmp/tidy-${tidy_version}.tgz
+curl --location "$tidy_package" > /tmp/tidy-${libtidy_version}.tgz
 
-mkdir -p /app/vendor/libtidy
-tar -xzv -C /app/vendor/libtidy -f /tmp/tidy-${tidy_version}.tgz
+mkdir --parents /app/vendor/libtidy
+tar --extract --gzip --directory=/app/vendor/libtidy --file=/tmp/tidy-${libtidy_version}.tgz
 
 pushd $php_src_dir/php-${php_version}/ext/tidy
 export PATH=$PATH:/app/vendor/php/bin
@@ -30,4 +33,3 @@ cp modules/tidy.so "$EXT_DIR"
 popd
 
 echo "extension=tidy.so" > "$PREFIX/etc/conf.d/tidy.ini"
-
diff --git a/support/ext/amqp b/support/ext/amqp
index d1bfc844..a341e372 100755
--- a/support/ext/amqp
+++ b/support/ext/amqp
@@ -229,4 +229,3 @@ echo "extension=amqp.so" > "${PREFIX}/etc/conf.d/amqp.ini"
 # Cleanup
 
 cleanup_amqp
-
diff --git a/support/ext/mongodb b/support/ext/mongodb
index 9b241536..ad915c92 100755
--- a/support/ext/mongodb
+++ b/support/ext/mongodb
@@ -26,6 +26,11 @@ curl --location "${url}" \
 
 pushd "mongodb-${mongodb_version}"
 
+if [ "$STACK" = "scalingo-26" ] && [ "${zend_api_version}" -ge "${PHP_MODULE_API_VERSIONS['8.5']}" ]; then
+	echo "Apply the patch to fix a call to IS_INTERNED"
+	patch -p1 < /buildpack/support/ext/mongodb-is-interned.patch
+fi
+
 if ! /app/vendor/php/bin/phpize; then
 	echo "Fail to PHPize mongodb extension"
 	exit 1
diff --git a/support/ext/mongodb-is-interned.patch b/support/ext/mongodb-is-interned.patch
new file mode 100644
index 00000000..30ec3b5b
--- /dev/null
+++ b/support/ext/mongodb-is-interned.patch
@@ -0,0 +1,13 @@
+diff --git a/src/contrib/php_array_api.h b/src/contrib/php_array_api.h
+index 5a97337..5e88c5c 100644
+--- a/src/contrib/php_array_api.h
++++ b/src/contrib/php_array_api.h
+@@ -350,7 +350,7 @@ char *php_array_zval_to_string(zval *z, int *plen, zend_bool *pfree) {
+ 			zval c = *z;
+ 			zval_copy_ctor(&c);
+ 			convert_to_string(&c);
+-			*pfree = ! IS_INTERNED(Z_STR(c));
++			*pfree = ! ZSTR_IS_INTERNED(Z_STR(c));
+ 			*plen = Z_STRLEN(c);
+ 			return Z_STRVAL(c);
+ 		}
diff --git a/support/get_gmp b/support/get_gmp
index 81fbb06a..9f58e183 100755
--- a/support/get_gmp
+++ b/support/get_gmp
@@ -25,7 +25,9 @@ curl --fail --location "https://gmplib.org/download/gmp/gmp-${gmp_version}.tar.x
 
 mkdir -p /app/vendor/gmp
 pushd "gmp-${gmp_version}" > /dev/null
-./configure --prefix=/app/vendor/gmp
+# We need the `CC` flag since gcc v15 (used in scalingo-26).
+# gcc v15 default C mode changed to C23 which made the configuration fails. A fix is already written but not yet published. Hence the `CC` flag may be deleted in the next releases.
+./configure --prefix=/app/vendor/gmp CC="gcc -std=gnu17"
 make
 make check
 make install
diff --git a/support/get_libc_client b/support/get_libc_client
index 2dd54f36..506b327e 100755
--- a/support/get_libc_client
+++ b/support/get_libc_client
@@ -45,6 +45,11 @@ elif [[ "${deps_stack}" = "scalingo-24" ]]; then
 		"https://archive.ubuntu.com/ubuntu/pool/universe/u/uw-imap/uw-imap_${dep_version}~dfsg-7.1.debian.tar.xz"
 		"https://archive.ubuntu.com/ubuntu/pool/universe/u/uw-imap/uw-imap_${dep_version}~dfsg-7.1.dsc"
 	)
+elif [[ "${deps_stack}" = "scalingo-26" ]]; then
+	dep_urls+=(
+		"https://archive.ubuntu.com/ubuntu/pool/universe/u/uw-imap/uw-imap_${dep_version}~dfsg-7.1.debian.tar.xz"
+		"https://archive.ubuntu.com/ubuntu/pool/universe/u/uw-imap/uw-imap_${dep_version}~dfsg-7.1.dsc"
+	)
 fi
 
 echo "-----> Downloading libc-client ${dep_version}"
diff --git a/support/get_libtidy b/support/get_libtidy
new file mode 100755
index 00000000..dbe1e28b
--- /dev/null
+++ b/support/get_libtidy
@@ -0,0 +1,47 @@
+#!/usr/bin/env bash
+#
+# This script downloads the libtidy version specified in libtidy_version. It compiles it and upload it to an object storage. Libtidy is eventually used when packaging the Tidy PHP extension (`support/ext-internal/tidy`), and during the deployment of a new PHP application (https://github.com/Scalingo/php-buildpack/blob/03f4e8f45bcff5dd307c23549d7c725b9ba63dff/lib/composer#L156-L157).
+#
+# This script must only be called in the context of the release of a new stack (https://www.notion.so/scalingooriginal/New-Stack-PHP-Support-d1e5370e886f41f492050a7a7536217f).
+#
+
+set -e
+if [ -n "$DEBUG" ]; then
+  set -x
+fi
+
+which cmake 2>/dev/null || (apt-get update && apt-get install -y cmake)
+
+basedir="$( cd -P "$( dirname "$0" )" && pwd )"
+
+# The variable is assigned in `versions.sh`
+declare libtidy_version
+source "$basedir/../conf/versions.sh"
+source "$basedir/lib/utils"
+source "$basedir/lib/swift"
+
+tempdir=$(mktmpdir libtidy)
+cd "$tempdir"
+
+echo "-----> Downloading libtidy v${libtidy_version}"
+curl --fail --location --remote-name "https://github.com/htacg/tidy-html5/archive/${libtidy_version}.tar.gz"
+
+tar xvf "${libtidy_version}.tar.gz"
+cd "tidy-html5-${libtidy_version}"
+mkdir --parents /app/vendor/libtidy
+
+cd build/cmake
+# The flag `-DCMAKE_POLICY_VERSION_MINIMUM=3.5` is mandatory for the call to CMake to succeed with versions available in scalingo-26 and more recent.
+cmake ../.. -DCMAKE_INSTALL_PREFIX=/app/vendor/libtidy -DTIDY_COMPAT_HEADERS=true -DCMAKE_POLICY_VERSION_MINIMUM=3.5
+make
+make install
+
+cd "$tempdir"
+mkdir package
+cd package
+tar -C /app/vendor/libtidy -czvf "libtidy-${libtidy_version}.tgz" .
+cd ..
+
+swift_upload "package/libtidy-${libtidy_version}.tgz"
+
+"$basedir/package-checksum" "libtidy-${libtidy_version}"
diff --git a/support/get_tidy b/support/get_tidy
deleted file mode 100755
index bc41795e..00000000
--- a/support/get_tidy
+++ /dev/null
@@ -1,41 +0,0 @@
-#!/usr/bin/env bash
-
-set -e
-if [ -n "$DEBUG" ]; then
-  set -x
-fi
-
-which cmake 2>/dev/null || (apt-get update && apt-get install -y cmake)
-
-basedir="$( cd -P "$( dirname "$0" )" && pwd )"
-
-# The variable is assigned in `versions.sh`
-declare tidy_version
-source "$basedir/../conf/versions.sh"
-source "$basedir/lib/utils"
-source "$basedir/lib/swift"
-
-tempdir=$(mktmpdir libtidy)
-cd "$tempdir"
-
-echo "-----> Downloading Tidy v${tidy_version}"
-curl --fail --location --remote-name "https://github.com/htacg/tidy-html5/archive/${tidy_version}.tar.gz"
-
-tar xvf "${tidy_version}.tar.gz"
-cd "tidy-html5-${tidy_version}"
-mkdir /app/vendor/libtidy
-
-cd build/cmake
-cmake ../.. -DCMAKE_INSTALL_PREFIX=/app/vendor/libtidy -DTIDY_COMPAT_HEADERS=true
-make
-make install
-
-cd "$tempdir"
-mkdir package
-cd package
-tar -C /app/vendor/libtidy -czvf "libtidy-${tidy_version}.tgz" .
-cd ..
-
-swift_upload "package/libtidy-${tidy_version}.tgz"
-
-"$basedir/package-checksum" "libtidy-${tidy_version}"
diff --git a/support/package_all b/support/package_all
index 0542a5a2..4ee2b1b7 100755
--- a/support/package_all
+++ b/support/package_all
@@ -29,9 +29,12 @@ source "../conf/versions.sh"
 #
 skip=( "imap" "igbinary" )
 
+echo "Compile the extensions for PHP $php_version"
+
 for e in ./ext-internal/*; do
 	ext_name="$( basename "${e}" )"
 
+  # For PHP 8.4 and more recent, we want to skip some extensions
 	if [[ "${PHP_MODULE_API_VERSIONS["${php_version}"]}" -ge 20240924 ]] \
 		&& [[ ${skip[@]} =~ "${ext_name}" ]]
 	then
@@ -48,6 +51,7 @@ done
 for e in ./ext/*; do
 	ext_name="$( basename "${e}" )"
 
+  # For PHP 8.4 and more recent, we want to skip some extensions
 	if [[ "${PHP_MODULE_API_VERSIONS["${php_version}"]}" -ge 20240924 ]] \
 		&& [[ ${skip[@]} =~ "${ext_name}" ]]
 	then
diff --git a/test/defaults b/test/defaults
index 57f6a713..1073a44b 100644
--- a/test/defaults
+++ b/test/defaults
@@ -17,6 +17,12 @@ default_nginx["scalingo-24"]="1.30."
 default_composer["scalingo-24"]="2.9."
 latest_composer["scalingo-24"]="2.9.8"
 
+# Defaults for scalingo-26:
+default_php["scalingo-26"]="8.4."
+default_nginx["scalingo-26"]="1.30."
+default_composer["scalingo-26"]="2.9."
+latest_composer["scalingo-26"]="2.9.8"
+
 
 test::defaults::classic() {
 #