diff --git a/.github/workflows/check-and-ebook.yml b/.github/workflows/check-and-ebook.yml
index 9bf93f8bf..4f7d3b81c 100644
--- a/.github/workflows/check-and-ebook.yml
+++ b/.github/workflows/check-and-ebook.yml
@@ -1,7 +1,6 @@
-# This workflow runs upon new commits (check and make) and PRs (check only)
-
 name: Check and Make eBook
 
+# This workflow runs upon new commits (check and make) and PRs (check only)
 on:
   workflow_dispatch:
   push:
@@ -22,13 +21,13 @@ jobs:
       cache-hit: ${{ steps.cache-lookup.outputs.cache-hit }}
 
     steps:
-      - name: checkout repository
+      - name: Check out repository
         uses: actions/checkout@v4
         with:
           persist-credentials: false
           fetch-depth: 1 # 0 if you want to push to repo
 
-      - name: calculate hash on chapters/*.tex
+      - name: Calculate hash on chapters/*.tex
         id: calculate-hash
         run: |
           current_date=$(date -u '+%Y-%m-%d')
@@ -36,29 +35,29 @@ jobs:
           echo "hash=${current_date}-${hashed}" >> $GITHUB_OUTPUT
           echo "${current_date}-${hashed}" > hash-chapters.txt
 
-      - name: cache lookup
+      - name: Cache lookup
         id: cache-lookup
         uses: actions/cache@v4
         with:
           path: hash-chapters.txt
           key: chapter-hash-for-ebook-${{ steps.calculate-hash.outputs.hash }}
 
-      - name: python set up
+      - name: Python set up
         uses: actions/setup-python@v5
         with:
-          python-version: "3.10"
+          python-version: "3.12"
           # cache: "pip"
 
-      - name: python cache set up
+      - name: Python cache set up
         uses: actions/cache@v4
         with:
           path: ${{ env.pythonLocation }}
           key: python-${{ env.pythonLocation }}
 
-      - name: check chapters for known issues
+      - name: Check chapters for known issues
         run: python3 -O scripts/check_chapters.py
 
-      - name: check pre-commit hooks
+      - name: Check pre-commit hooks
         uses: pre-commit/action@v3.0.1
 
   #
@@ -72,16 +71,16 @@ jobs:
     runs-on: ubuntu-22.04
 
     steps:
-      - name: checkout repository
+      - name: Check out repository
         uses: actions/checkout@v4
         with:
           persist-credentials: false
           fetch-depth: 1 # 0 if you want to push to repo
 
-      - name: python set up
+      - name: Python set up
         uses: actions/setup-python@v5
         with:
-          python-version: "3.10"
+          python-version: "3.12"
           # cache: "pip"
 
       #  - name: setup environment to DE lang
@@ -95,14 +94,14 @@ jobs:
           ls -l
           echo ${{ needs.check.outputs.cache-hit }}
 
-      - name: install apt packages using cache
+      - name: Install apt packages using cache
         uses: awalsh128/cache-apt-pkgs-action@latest
         with:
           packages: texlive-extra-utils pandoc calibre imagemagick ghostscript
           version: 1.0
           # execute_install_scripts: true
 
-      - name: print versions
+      - name: Print versions
         run: |
           cat /etc/os-release
           # xelatex -v
@@ -111,7 +110,7 @@ jobs:
           pandoc --version
           python3 --version
 
-      - name: make eBooks
+      - name: Make eBooks
         run: |
           wget --quiet https://github.com/entorb/hpmor-de/releases/download/WorkInProgress/hpmor.pdf -O hpmor.pdf
           sh scripts/make_ebooks.sh > /dev/null
@@ -121,7 +120,7 @@ jobs:
           pwd
           ls -l
 
-      - name: publish eBooks to release
+      - name: Publish eBooks to release
         uses: softprops/action-gh-release@v2
         with:
           tag_name: WorkInProgress
diff --git a/.github/workflows/make-pdf-1-select.yml b/.github/workflows/make-pdf-1-select.yml
index 92146fc68..4c1569813 100644
--- a/.github/workflows/make-pdf-1-select.yml
+++ b/.github/workflows/make-pdf-1-select.yml
@@ -13,14 +13,14 @@ jobs:
   build:
     runs-on: ubuntu-22.04
     steps:
-      - name: print selection
+      - name: Print selection
         run: |
           echo "selected PDF: ${{ github.event.inputs.pdf_target }}"
 
-      - name: print start date
+      - name: Print start date
         run: date +%Y-%m-%d_%H:%M
 
-      - name: checkout repository
+      - name: Check out repository
         uses: actions/checkout@v4
         with:
           persist-credentials: false
@@ -43,10 +43,10 @@ jobs:
       - name: ls chapters
         run: ls -l chapters/
 
-      - name: python set up
+      - name: Python set up
         uses: actions/setup-python@v5
         with:
-          python-version: "3.10"
+          python-version: "3.12"
           # cache: "pip"
 
       - name: ls before
@@ -54,16 +54,16 @@ jobs:
           pwd
           ls -l
 
-      - name: check chapters for known issues
+      - name: Check chapters for known issues
         run: python3 -O scripts/check_chapters.py
 
-      - name: install PDF requirements
+      - name: Install PDF requirements
         run: |
           # not: to save time
-          # sudo apt update > /dev/null
+          # sudo apt-get update > /dev/null
           sh scripts/install_requirements_pdf.sh > /dev/null
 
-      - name: print versions
+      - name: Print versions
         run: |
           cat /etc/os-release
           xelatex -v
@@ -71,11 +71,11 @@ jobs:
           # pandoc -v
           python3 --version
 
-      - name: make PDF
+      - name: Make PDF
         run: |
           latexmk "${{ github.event.inputs.pdf_target }}" > /dev/null
 
-      - name: publish PDF to release
+      - name: Publish PDF to release
         uses: softprops/action-gh-release@v2
         with:
           tag_name: WorkInProgress
@@ -83,7 +83,7 @@ jobs:
           files: |
             ./hpmor*.pdf
 
-      - name: upload log as artifact
+      - name: Upload log as artifact
         uses: actions/upload-artifact@v4
         with:
           name: "${{ github.event.inputs.pdf_target }}.log"
@@ -93,5 +93,5 @@ jobs:
         run: |
           ls -l
 
-      - name: print end date
+      - name: Print end date
         run: date +%Y-%m-%d_%H:%M
diff --git a/.github/workflows/make-pdf-6-parallel.yml b/.github/workflows/make-pdf-6-parallel.yml
index e715e5451..314069081 100644
--- a/.github/workflows/make-pdf-6-parallel.yml
+++ b/.github/workflows/make-pdf-6-parallel.yml
@@ -11,13 +11,13 @@ jobs:
       matrix:
         part: [hpmor-1, hpmor-2, hpmor-3, hpmor-4, hpmor-5, hpmor-6]
     steps:
-      - name: checkout repository
+      - name: Check out repository
         uses: actions/checkout@v4
         with:
           persist-credentials: false
           fetch-depth: 1 # 0 if you want to push to repo
 
-      - name: cache LaTeX files
+      - name: Cache LaTeX files
         uses: actions/cache@v4
         with:
           path: |
@@ -31,23 +31,23 @@ jobs:
             hpmor*.xdv
           key: latex-build-files
 
-      - name: install PDF requirements
+      - name: Install PDF requirements
         run: |
           # not: to save time
-          # sudo apt update > /dev/null
+          # sudo apt-get update > /dev/null
           sh scripts/install_requirements_pdf.sh > /dev/null
 
-      - name: make PDF
+      - name: Make PDF
         run: latexmk ${{ matrix.part }} > /dev/null
 
-      - name: publish PDF to release
+      - name: Publish PDF to release
         uses: softprops/action-gh-release@v2
         with:
           tag_name: WorkInProgress
           prerelease: true
           files: ${{ matrix.part }}.pdf
 
-      - name: upload log as artifact
+      - name: Upload log as artifact
         uses: actions/upload-artifact@v4
         with:
           name: "${{ matrix.part }}.log"
diff --git a/.github/workflows/make-pdf-all-serial.yml b/.github/workflows/make-pdf-all-serial.yml
index 8a8d647d7..c5fb6b7b1 100644
--- a/.github/workflows/make-pdf-all-serial.yml
+++ b/.github/workflows/make-pdf-all-serial.yml
@@ -8,13 +8,13 @@ jobs:
   build:
     runs-on: ubuntu-22.04
     steps:
-      - name: checkout repository
+      - name: Check out repository
         uses: actions/checkout@v4
         with:
           persist-credentials: false
           fetch-depth: 1 # 0 if you want to push to repo
 
-      - name: caching LaTeX files
+      - name: Cache LaTeX files
         uses: actions/cache@v4
         with:
           path: |
@@ -28,12 +28,12 @@ jobs:
             hpmor*.xdv
           key: latex-build-files
 
-      - name: install PDF requirements
+      - name: Install PDF requirements
         run: |
-          sudo apt update > /dev/null
+          sudo apt-get update > /dev/null
           sh scripts/install_requirements_pdf.sh > /dev/null
 
-      - name: print versions
+      - name: Print versions
         run: |
           cat /etc/os-release
           xelatex -v
@@ -41,7 +41,7 @@ jobs:
           # pandoc -v
           python3 --version
 
-      - name: make PDFs
+      - name: Make PDFs
         run: latexmk hpmor-1 hpmor-2 hpmor-3 hpmor-4 hpmor-5 hpmor-6 hpmor > /dev/null
 
       - name: Publish PDF to release
@@ -51,7 +51,7 @@ jobs:
           prerelease: true
           files: hpmor*.pdf
 
-      - name: upload logs as artifact
+      - name: Upload logs as artifact
         uses: actions/upload-artifact@v4
         with:
           name: "hpmor.log"
diff --git a/.github/workflows/make-pdf-test.yml b/.github/workflows/make-pdf-test.yml
index c11e2837b..84877d358 100644
--- a/.github/workflows/make-pdf-test.yml
+++ b/.github/workflows/make-pdf-test.yml
@@ -21,7 +21,7 @@ jobs:
       - name: Python set up
         uses: actions/setup-python@v5
         with:
-          python-version: "3.10"
+          python-version: "3.12"
           # cache: "pip"
 
       - name: Test ls before
@@ -31,11 +31,11 @@ jobs:
 
       - name: Install requirements
         run: |
-          sudo apt update > /dev/null
+          sudo apt-get update > /dev/null
           sh scripts/install_requirements_pdf.sh > /dev/null
 
       # unfortunately not working
-      # - name: cache packages
+      # - name: Cache packages
       #   uses: awalsh128/cache-apt-pkgs-action@latest
       #   with:
       #     packages: texlive-xetex texlive-lang-german latexmk
@@ -54,7 +54,7 @@ jobs:
         #      run: sh scripts/make_pdf.sh > /dev/null
         run: latexmk layout/test -f
 
-      # - name: publish log to release
+      # - name: Publish log to release
       #   uses: softprops/action-gh-release@v2
       #   with:
       #     tag_name: WorkInProgress
diff --git a/.pre-commit-config.yaml b/.pre-commit-config.yaml
index e45442f24..a986d21a6 100644
--- a/.pre-commit-config.yaml
+++ b/.pre-commit-config.yaml
@@ -90,4 +90,4 @@ repos:
         args: ["--disable", "MD013"]
 
 default_language_version:
-  python: python3.10
+  python: python3.12
diff --git a/.ruff.toml b/.ruff.toml
index 074665cf1..fa7b32fd4 100644
--- a/.ruff.toml
+++ b/.ruff.toml
@@ -1,6 +1,6 @@
 fix = true               # auto-fix findings
 line-length = 88         # same as Black
-target-version = "py310" # Python 3.10
+target-version = "py312" # Python 3.12
 
 [lint]
 # comment this out to use only default rules (["E4", "E7", "E9", "F"])
diff --git a/scripts/ebook/step_3.py b/scripts/ebook/step_3.py
index 93f73be59..56ab49e33 100755
--- a/scripts/ebook/step_3.py
+++ b/scripts/ebook/step_3.py
@@ -22,7 +22,7 @@
         cont = fh_in.read()
 
     # \today
-    date_str = dt.datetime.now(dt.timezone.utc).date().strftime("%d.%m.%Y")
+    date_str = dt.datetime.now(dt.UTC).date().strftime("%d.%m.%Y")
     cont = cont.replace("\\today{}", date_str)
 
     # writtenNote env -> \writtenNoteA
diff --git a/scripts/install_requirements_ebook.sh b/scripts/install_requirements_ebook.sh
index 53c3dcac9..53110fed6 100755
--- a/scripts/install_requirements_ebook.sh
+++ b/scripts/install_requirements_ebook.sh
@@ -1,6 +1,6 @@
 #!/bin/sh
 
-sudo apt install texlive-extra-utils pandoc calibre imagemagick ghostscript
+sudo apt-get install texlive-extra-utils pandoc calibre imagemagick ghostscript
 # pandoc calibre : for ebook converting
 # texlive-extra-utils : for latexpand
 # imagemagick ghostscript : for pdf title page to image conversion
diff --git a/scripts/install_requirements_pdf.sh b/scripts/install_requirements_pdf.sh
index 35a97ec71..79703953d 100755
--- a/scripts/install_requirements_pdf.sh
+++ b/scripts/install_requirements_pdf.sh
@@ -1,3 +1,3 @@
 #!/bin/sh
 
-sudo apt install texlive-xetex texlive-lang-german latexmk
+sudo apt-get install texlive-xetex texlive-lang-german latexmk