diff --git a/docs/build.rst b/docs/build.rst
index 46764aa7..754c2865 100644
--- a/docs/build.rst
+++ b/docs/build.rst
@@ -208,7 +208,7 @@ for IoT applications.
 It has two Ethernet ports, on-board Wi-Fi and Bluetooth, a micro SD card slot
 and two USB ports. It takes power from its micro USB port.
 
-Debian (bullseye) will be loaded on the microSD card and will include the MTDA
+Debian (bookworm) will be loaded on the microSD card and will include the MTDA
 agent. It will communicate with its clients over Ethernet. An electric relay
 will be controlled via USB to drive power for our Device Under Test.
 Communication with that device will be achieved via the USB OTG port where the
@@ -329,7 +329,7 @@ FriendlyARM for makers, hobbyists and fans.
 It is powered by an Allwinner H3 (Cortex A7), has a microSD slot, a microUSB
 OTG port, a USB-Host Type A port, an Ethernet port and GPIO pins.
 
-Debian (bullseye) will be loaded on the microSD card and will include the MTDA
+Debian (bookworm) will be loaded on the microSD card and will include the MTDA
 agent. It will communicate with its clients over Ethernet. An electric relay
 will be controlled via a GPIO line in order to drive power for our Device Under
 Test. Communication with that device will be achieved via the USB OTG port
diff --git a/docs/install.rst b/docs/install.rst
index 0b56fa00..7c7e2b29 100644
--- a/docs/install.rst
+++ b/docs/install.rst
@@ -1,10 +1,10 @@
 Installation
 ============
 
-Using apt on Debian 11
+Using apt on Debian 12
 ----------------------
 
-Packages for Debian 11 (bullseye) may be installed as follows::
+Packages for Debian 12 (bookworm) may be installed as follows::
 
    $ echo 'deb [trusted=yes] https://apt.fury.io/mtda/ /' | \
      sudo tee /etc/apt/sources.list.d/mtda.list
diff --git a/kas/debian/bullseye-base.yml b/kas/debian/bullseye-base.yml
deleted file mode 100644
index bec8a1f4..00000000
--- a/kas/debian/bullseye-base.yml
+++ /dev/null
@@ -1,17 +0,0 @@
-# ---------------------------------------------------------------------------
-# Base kas file for all configurations based on Debian bullseye
-# ---------------------------------------------------------------------------
-#
-# This software is a part of MTDA.
-# Copyright (C) 2023 Siemens Digital Industries Software
-#
-# ---------------------------------------------------------------------------
-# SPDX-License-Identifier: MIT
-# ---------------------------------------------------------------------------
-
-header:
-  version: 10
-  includes:
-    - kas/common/base.yml
-
-distro: mtda-bullseye
diff --git a/meta-isar/conf/apt/debian-bullseye-backports.conf b/meta-isar/conf/apt/debian-bullseye-backports.conf
deleted file mode 100644
index 417f0eb3..00000000
--- a/meta-isar/conf/apt/debian-bullseye-backports.conf
+++ /dev/null
@@ -1,14 +0,0 @@
-# ---------------------------------------------------------------------------
-# This apt configuration file is part of MTDA
-# Copyright (C) 2021 Siemens Digital Industries Software
-# ---------------------------------------------------------------------------
-# SPDX-License-Identifier: MIT
-# ---------------------------------------------------------------------------
-
-Package: *
-Pin: release n=bullseye-backports
-Pin-Priority: -1
-
-Package: linux-image-*armmp
-Pin: release n=bullseye-backports
-Pin-Priority: 501
diff --git a/meta-isar/conf/apt/debian-bullseye-backports.list b/meta-isar/conf/apt/debian-bullseye-backports.list
deleted file mode 100644
index f2820bdd..00000000
--- a/meta-isar/conf/apt/debian-bullseye-backports.list
+++ /dev/null
@@ -1,9 +0,0 @@
-# ---------------------------------------------------------------------------
-# This apt configuration file is part of MTDA
-# Copyright (C) 2021 Siemens Digital Industries Software
-# ---------------------------------------------------------------------------
-# SPDX-License-Identifier: MIT
-# ---------------------------------------------------------------------------
-
-deb	http://deb.debian.org/debian bullseye-backports main contrib non-free
-deb-src	http://deb.debian.org/debian bullseye-backports main contrib non-free
diff --git a/meta-isar/conf/distro/mtda-bullseye.conf b/meta-isar/conf/distro/mtda-bullseye.conf
deleted file mode 100644
index e41a6a65..00000000
--- a/meta-isar/conf/distro/mtda-bullseye.conf
+++ /dev/null
@@ -1,11 +0,0 @@
-# ---------------------------------------------------------------------------
-# This Isar layer is part of MTDA
-# Copyright (C) 2023 Siemens Digital Industries Software
-# ---------------------------------------------------------------------------
-# SPDX-License-Identifier: MIT
-# ---------------------------------------------------------------------------
-
-require conf/distro/debian-bullseye.conf
-
-DISTRO_APT_PREFERENCES:append = " conf/apt/debian-bullseye-backports.conf"
-DISTRO_APT_SOURCES:append = " conf/apt/debian-bullseye-backports.list"
diff --git a/meta-isar/conf/multiconfig/nanopi-neo.conf b/meta-isar/conf/multiconfig/nanopi-neo.conf
index 35e2b003..f5074bdb 100644
--- a/meta-isar/conf/multiconfig/nanopi-neo.conf
+++ b/meta-isar/conf/multiconfig/nanopi-neo.conf
@@ -5,5 +5,5 @@
 # SPDX-License-Identifier: MIT
 # ---------------------------------------------------------------------------
 
-DISTRO = "mtda-bullseye"
+DISTRO = "mtda-bookworm"
 MACHINE = "nanopi-neo"
diff --git a/meta-isar/conf/multiconfig/nanopi-r1.conf b/meta-isar/conf/multiconfig/nanopi-r1.conf
index f850e918..cd10421b 100644
--- a/meta-isar/conf/multiconfig/nanopi-r1.conf
+++ b/meta-isar/conf/multiconfig/nanopi-r1.conf
@@ -5,5 +5,5 @@
 # SPDX-License-Identifier: MIT
 # ---------------------------------------------------------------------------
 
-DISTRO = "mtda-bullseye"
+DISTRO = "mtda-bookworm"
 MACHINE = "nanopi-r1"
diff --git a/meta-isar/recipes-python/mtda/mtda_git.bb b/meta-isar/recipes-python/mtda/mtda_git.bb
index 25232854..7df86ffe 100644
--- a/meta-isar/recipes-python/mtda/mtda_git.bb
+++ b/meta-isar/recipes-python/mtda/mtda_git.bb
@@ -36,7 +36,6 @@ SRC_URI += "${@' '.join(['file://' + d.getVar('LAYERDIR_mtda') + '/../' + file f
 S = "${WORKDIR}/working-repo"
 
 DEPENDS += "zerorpc-python kconfiglib py3qterm"
-DEPENDS:append:bullseye = " zstandard"
 
 do_gen_working_repo() {
 	for file in ${MTDA_FILES}; do