diff --git a/.github/workflows/build-test-release.yml b/.github/workflows/build-test-release.yml
index 887df95080..e35c40326f 100644
--- a/.github/workflows/build-test-release.yml
+++ b/.github/workflows/build-test-release.yml
@@ -20,7 +20,7 @@ concurrency:
 jobs:
   acquire-python-version-build-sdist:
     name: Build sdist and set version
-    runs-on: ubuntu-24.04
+    runs-on: ubuntu-26.04
     steps:
       - uses: actions/checkout@3d3c42e5aac5ba805825da76410c181273ba90b1 # v7.0.1
 
@@ -50,7 +50,7 @@ jobs:
           path: ./wheelhouse/*.tar.gz
 
   build-cpp-test-linux:
-    runs-on: ubuntu-24.04
+    runs-on: ubuntu-26.04
     strategy:
       matrix:
         build-option: [debug, release]
@@ -164,10 +164,10 @@ jobs:
         platform: [linux-x64, linux-aarch64, macos-arm64, macos-x64, windows]
         include:
           - platform: linux-x64
-            os: ubuntu-24.04
+            os: ubuntu-26.04
             cibw_build: "*_x86_64"
           - platform: linux-aarch64
-            os: ubuntu-24.04-arm
+            os: ubuntu-26.04-arm
             cibw_build: "*_aarch64"
           - platform: macos-arm64
             os: macos-26
diff --git a/.github/workflows/check-build-reproducibility.yml b/.github/workflows/check-build-reproducibility.yml
index 2e62f4547e..70766aebca 100644
--- a/.github/workflows/check-build-reproducibility.yml
+++ b/.github/workflows/check-build-reproducibility.yml
@@ -19,7 +19,7 @@ jobs:
   check-power-grid-model-c-linux:
     strategy:
       matrix:
-        os: [ubuntu-latest, ubuntu-24.04-arm]
+        os: [ubuntu-26.04, ubuntu-26.04-arm]
         compiler: [gcc, clang]
 
     runs-on: ${{ matrix.os }}
diff --git a/.github/workflows/check-code-quality.yml b/.github/workflows/check-code-quality.yml
index c4a2444004..a694009332 100644
--- a/.github/workflows/check-code-quality.yml
+++ b/.github/workflows/check-code-quality.yml
@@ -21,7 +21,7 @@ concurrency:
 jobs:
   check-code-quality:
 
-    runs-on: ubuntu-24.04
+    runs-on: ubuntu-26.04
 
     steps:
       - name: Checkout
diff --git a/.github/workflows/citations.yml b/.github/workflows/citations.yml
index c0dbe8f0a8..05aab03227 100644
--- a/.github/workflows/citations.yml
+++ b/.github/workflows/citations.yml
@@ -27,7 +27,7 @@ concurrency:
 
 jobs:
   validate-citations:
-    runs-on: ubuntu-24.04
+    runs-on: ubuntu-26.04
     steps:
     - name: checkout
       uses: actions/checkout@3d3c42e5aac5ba805825da76410c181273ba90b1 # v7.0.1
diff --git a/.github/workflows/clang-tidy.yml b/.github/workflows/clang-tidy.yml
index 5a039899ef..85f9624a0b 100644
--- a/.github/workflows/clang-tidy.yml
+++ b/.github/workflows/clang-tidy.yml
@@ -36,7 +36,7 @@ concurrency:
 
 jobs:
   clang-tidy:
-    runs-on: ubuntu-24.04
+    runs-on: ubuntu-26.04
     strategy:
       matrix:
         build-option: [ debug, release ]
diff --git a/.github/workflows/reuse-compliance.yml b/.github/workflows/reuse-compliance.yml
index 2bfe22928b..0632f8d4cb 100644
--- a/.github/workflows/reuse-compliance.yml
+++ b/.github/workflows/reuse-compliance.yml
@@ -16,7 +16,7 @@ concurrency:
 
 jobs:
   reuse-compliance-check:
-    runs-on: ubuntu-24.04
+    runs-on: ubuntu-26.04
     steps:
     - name: checkout
       uses: actions/checkout@3d3c42e5aac5ba805825da76410c181273ba90b1 # v7.0.1
diff --git a/.github/workflows/sonar.yml b/.github/workflows/sonar.yml
index 9a4cdf07db..d247e157ea 100644
--- a/.github/workflows/sonar.yml
+++ b/.github/workflows/sonar.yml
@@ -21,7 +21,7 @@ concurrency:
 jobs:
   sonar-cloud:
     name: SonarCloud
-    runs-on: ubuntu-24.04
+    runs-on: ubuntu-26.04
     env:
       BUILD_WRAPPER_OUT_DIR: build_wrapper_output_directory # Directory where build-wrapper output will be placed
       CMAKE_PREFIX_PATH: /home/linuxbrew/.linuxbrew
diff --git a/.github/workflows/thread-sanitizer.yml b/.github/workflows/thread-sanitizer.yml
index 78b2f3e7f8..fef6785db7 100644
--- a/.github/workflows/thread-sanitizer.yml
+++ b/.github/workflows/thread-sanitizer.yml
@@ -19,7 +19,7 @@ concurrency:
 
 jobs:
   thread-sanitizer-linux:
-    runs-on: ubuntu-24.04
+    runs-on: ubuntu-26.04
     strategy:
       matrix:
         build-option: [debug, release]
diff --git a/.readthedocs.yaml b/.readthedocs.yaml
index 6ac3f1ca39..9651dc1aba 100644
--- a/.readthedocs.yaml
+++ b/.readthedocs.yaml
@@ -9,9 +9,11 @@ sphinx:
   configuration: docs/conf.py
 
 build:
-  os: "ubuntu-24.04"
+  os: "ubuntu-26.04"
   apt_packages:
     - graphviz
+    - graphviz-tools
+    - libgvplugin-neato-layout8
     - gcc-14
     - g++-14
   tools:
diff --git a/docs/advanced_documentation/build-guide.md b/docs/advanced_documentation/build-guide.md
index 2a3d1dc94b..9984dc077d 100644
--- a/docs/advanced_documentation/build-guide.md
+++ b/docs/advanced_documentation/build-guide.md
@@ -36,7 +36,7 @@ It automatically sets up the entire environment so you can start developing imme
 
 To build the library from source, you need to first prepare the compiler toolchains and the build dependencies.
 In this section a list of general requirements are given.
-After this section there are examples of setup in Linux (Ubuntu 24.04), Windows 11, and macOS (Tahoe).
+After this section there are examples of setup in Linux (Ubuntu 26.04), Windows 11, and macOS (Tahoe).
 
 ### Architecture Support
 
@@ -245,9 +245,9 @@ Usage: ./build.sh -p <preset> [-c] [-e] [-i] [-t]
 
 To list the available presets, run `./build.sh -h`.
 
-## Example Setup for Ubuntu 24.04 (in WSL or physical/virtual machine)
+## Example Setup for Ubuntu 26.04 (in WSL or physical/virtual machine)
 
-In this section an example is given for setup in Ubuntu 24.04.
+In this section an example is given for setup in Ubuntu 26.04.
 You can use this example in Windows Subsystem for Linux (WSL), or in a physical/virtual machine.
 
 While you can use `apt`, setup via [Homebrew](https://brew.sh) has proved to be much simpler.
diff --git a/tests/cpp_unit_tests/math_solver/test_math_solver_se.hpp b/tests/cpp_unit_tests/math_solver/test_math_solver_se.hpp
index 3df46ef009..82211d5ecd 100644
--- a/tests/cpp_unit_tests/math_solver/test_math_solver_se.hpp
+++ b/tests/cpp_unit_tests/math_solver/test_math_solver_se.hpp
@@ -809,9 +809,9 @@ TEST_CASE_TEMPLATE_DEFINE("Test math solver - SE, measurements", SolverType, tes
         // NRSE solver
         CHECK(true);
     } else {
-        CHECK(output.bus_injection[0] == output.branch[0].s_f);
-        CHECK(output.bus_injection[0] == output.source[0].s);
-        CHECK(output.bus_injection[1] == output.branch[0].s_t);
+        check_close(output.bus_injection[0], output.branch[0].s_f);
+        check_close(output.bus_injection[0], output.source[0].s);
+        check_close(output.bus_injection[1], output.branch[0].s_t);
         CHECK(real(output.bus_injection[1]) == doctest::Approx(real(load_gen_s)));
     }
 }