diff --git a/.github/actions/nix-update-action/action.yaml b/.github/actions/nix-update-action/action.yaml
new file mode 100644
index 0000000..ea3b481
--- /dev/null
+++ b/.github/actions/nix-update-action/action.yaml
@@ -0,0 +1,100 @@
+name: 'nix-update action'
+description: 'A GitHub action that detects and updates flake outputs via nix-update tool'
+inputs:
+  token:
+    description: 'The token that the action will use to create and update the pull request.'
+    default: ${{ github.token }}
+  packages:
+    description: 'A space-separated list of inputs to update. Leave empty to update all inputs.'
+    required: false
+    default: ''
+  blacklist:
+    description: 'A list of dependencies, comma separated, to skip from updating.'
+    required: false
+    default: ''
+  branch:
+    description: 'The branch of the PR to be created'
+    required: false
+    default: "chore/nix_update_actions"
+  path-to-flake-dir:
+    description: 'The path of the directory containing `flake.nix` file within your repository.'
+    required: false
+    default: ''
+  pr-title:
+    description: 'The title of the PR to be created'
+    required: false
+    default: "Packages: update"
+  pr-body:
+    description: 'The body of the PR to be created'
+    required: false
+    default: |
+      Automated changes by the [nix-update-actions](https://github.com/selfuryon/nix-update-action) GitHub Action.
+  pr-labels:
+    description: 'A comma or newline separated list of labels to set on the Pull Request to be created'
+    required: false
+    default: ''
+  pr-assignees:
+    description: 'A comma or newline separated list of assignees (GitHub usernames).'
+    required: false
+    default: ''
+  pr-reviewers:
+    description: 'A comma or newline separated list of reviewers (GitHub usernames) to request a review from.'
+    required: false
+    default: ''
+  git-author-name:
+    description: 'Author name used for commit.'
+    required: false
+    default: 'github-actions[bot]'
+  git-author-email:
+    description: 'Author email used for commit.'
+    required: false
+    default: 'github-actions[bot]@users.noreply.github.com'
+  git-committer-name:
+    description: 'Committer name used for commit.'
+    required: false
+    default: 'github-actions[bot]'
+  git-committer-email:
+    description: 'Committer email used for commit.'
+    required: false
+    default: 'github-actions[bot]@users.noreply.github.com'
+outputs:
+  pull-request-number:
+    description: 'The number of the opened pull request'
+    value: ${{ steps.create-pr.outputs.pull-request-number }}
+runs:
+  using: "composite"
+  steps:
+    - uses: yaxitech/nix-install-pkgs-action@v3
+      with:
+        packages: "nix-update,jq"
+        inputs-from: nixpkgs
+    - name: Set environment variables
+      shell: bash
+      run: |
+        echo "GIT_AUTHOR_NAME=${{ inputs.git-author-name }}" >> $GITHUB_ENV
+        echo "GIT_AUTHOR_EMAIL=<${{ inputs.git-author-email }}>" >> $GITHUB_ENV
+        echo "GIT_COMMITTER_NAME=${{ inputs.git-committer-name }}" >> $GITHUB_ENV
+        echo "GIT_COMMITTER_EMAIL=<${{ inputs.git-committer-email }}>" >> $GITHUB_ENV
+    - name: Run nix-update
+      run: $GITHUB_ACTION_PATH/nix-update.sh
+      shell: bash
+      env:
+        PACKAGES: ${{ inputs.packages }}
+        BLACKLIST: ${{ inputs.blacklist }}
+        GIT_AUTHOR_NAME: ${{ env.GIT_AUTHOR_NAME }}
+        GIT_AUTHOR_EMAIL: ${{ env.GIT_AUTHOR_EMAIL }}
+        GIT_COMMITTER_NAME: ${{ env.GIT_COMMITTER_NAME }}
+        GIT_COMMITTER_EMAIL: ${{ env.GIT_COMMITTER_EMAIL }}
+        PATH_TO_FLAKE_DIR: ${{ inputs.path-to-flake-dir }}
+    - name: Create PR
+      id: create-pr
+      uses: peter-evans/create-pull-request@v4
+      with:
+        token: ${{ inputs.token }}
+        branch: ${{ inputs.branch }}
+        delete-branch: true
+        title: ${{ inputs.pr-title }}
+        assignees: ${{ inputs.pr-assignees }}
+        labels: ${{ inputs.pr-labels }}
+        reviewers: ${{ inputs.pr-reviewers }}
+        body: ${{ inputs.pr-body }}
diff --git a/.github/actions/nix-update-action/nix-update.sh b/.github/actions/nix-update-action/nix-update.sh
new file mode 100755
index 0000000..e7501ce
--- /dev/null
+++ b/.github/actions/nix-update-action/nix-update.sh
@@ -0,0 +1,38 @@
+#!/usr/bin/env bash
+set -euo pipefail
+
+enterFlakeFolder() {
+  if [[ -n "$PATH_TO_FLAKE_DIR" ]]; then
+    cd "$PATH_TO_FLAKE_DIR"
+  fi
+}
+
+sanitizeInputs() {
+  # remove all whitespace
+  PACKAGES="${PACKAGES// /}"
+  BLACKLIST="${BLACKLIST// /}"
+}
+
+determinePackages() {
+  # determine packages to update
+  if [[ -z "$PACKAGES" ]]; then
+    PACKAGES=$(nix flake show --json | jq -r '[.packages[] | keys[]] | sort | unique |  join(",")')
+  fi
+}
+
+updatePackages() {
+  # update packages
+  for PACKAGE in ${PACKAGES//,/ }; do
+    if [[ ",$BLACKLIST," == *",$PACKAGE,"* ]]; then
+        echo "Package '$PACKAGE' is blacklisted, skipping."
+        continue
+    fi
+    echo "Updating package '$PACKAGE'."
+    nix-update --flake --commit "$PACKAGE" 1>/dev/null
+  done
+}
+
+enterFlakeFolder
+sanitizeInputs
+determinePackages
+updatePackages
diff --git a/.github/workflows/update-flake-packages.yml b/.github/workflows/update-flake-packages.yml
index d8a35de..3ac6a54 100644
--- a/.github/workflows/update-flake-packages.yml
+++ b/.github/workflows/update-flake-packages.yml
@@ -12,7 +12,8 @@ jobs:
       - name: Install nix
         uses: cachix/install-nix-action@v30
       - name: Update flake packages
-        uses: selfuryon/nix-update-action@v1.0.1
+        uses: ./.github/actions/nix-update-action
         with:
+          token: ${{ secrets.GH_TOKEN }}
           blacklist: "polkadot,subkey,zombienet"
           pr-title: "bot: update packages"
diff --git a/pkgs/graypaper/default.nix b/pkgs/graypaper/default.nix
index a40b2f1..6e75390 100644
--- a/pkgs/graypaper/default.nix
+++ b/pkgs/graypaper/default.nix
@@ -5,7 +5,7 @@
 }:
 
 let
-  version = "0.4.4";
+  version = "0.4.5";
 in
 runCommand "graypaper"
   {
@@ -15,7 +15,7 @@ runCommand "graypaper"
       owner = "gavofyork";
       repo = "graypaper";
       rev = "v${version}";
-      hash = "sha256-YpKkGLchDKNhoezbVUmcddR1uRFf5b2rxOKafVn28rE=";
+      hash = "sha256-56Y5psJVNhRLPcGvCt4IqQ39d7144IdDcGOOoO6pvdE=";
     };
     nativeBuildInputs = [
       (texliveBasic.withPackages (