diff --git a/.github/workflows/build-and-push-shared.yml b/.github/workflows/build-and-push-shared.yml
index 7a7047ec..99813bac 100644
--- a/.github/workflows/build-and-push-shared.yml
+++ b/.github/workflows/build-and-push-shared.yml
@@ -80,7 +80,7 @@ jobs:
 
       - name: Set image tag output
         id: set-tag
-        run: echo "::set-output name=image-tag::${{ steps.meta.outputs.version }}"    
+        run: echo "image-tag=${{ steps.meta.outputs.version }}" >> $GITHUB_OUTPUT
 
       - name: Build and push Docker Image
         uses: docker/build-push-action@v6
diff --git a/.github/workflows/deploy-dev.yml b/.github/workflows/deploy-dev.yml
index 59c1b95a..5b2a4b9d 100644
--- a/.github/workflows/deploy-dev.yml
+++ b/.github/workflows/deploy-dev.yml
@@ -1,21 +1,32 @@
-name: Deploy Dev
+name: Deploy to Dev
 
 on:
   workflow_dispatch:
     inputs:
       image-tag:
         type: string
-        description: "The tag of the docker images to deploy"
-        required: true
-jobs:
+        description: "Image tag to deploy (default: pr-<number> if PR exists, latest for default branch)"
+
+jobs:  
+  prepare-env:
+    runs-on: ubuntu-latest
+    environment: Dev
+    outputs:
+      env-vars: |
+        DEPLOYMENT_URL=${{ vars.DEPLOYMENT_URL }}
+        APOLLON_REDIS_DIAGRAM_TTL=${{ vars.APOLLON_REDIS_DIAGRAM_TTL }}
+    steps:
+      - name: Do nothing
+        run: echo "Nothing to do here"
+
   deploy:
+    needs: prepare-env
     # TODO: uses: ls1intum/.github/.github/workflows/deploy-docker-compose.yml@main
     uses: ./.github/workflows/deploy-docker-compose-shared.yml
     with:
       environment: Dev
       docker-compose-file: "./docker-compose.prod.yml"
+      main-image-name: ls1intum/apollon_standalone
       image-tag: ${{ inputs.image-tag }}
-      env-vars: |
-        DEPLOYMENT_URL=${{ vars.DEPLOYMENT_URL }}
-        APOLLON_REDIS_DIAGRAM_TTL=${{ vars.APOLLON_REDIS_DIAGRAM_TTL }}
+      env-vars: ${{ needs.prepare-env.outputs.env-vars }}
     secrets: inherit
diff --git a/.github/workflows/deploy-docker-compose-shared.yml b/.github/workflows/deploy-docker-compose-shared.yml
index a5e2827c..76821c14 100644
--- a/.github/workflows/deploy-docker-compose-shared.yml
+++ b/.github/workflows/deploy-docker-compose-shared.yml
@@ -12,25 +12,77 @@ on:
         type: string
         default: "./docker-compose.yml"
         description: "Path to the Docker Compose file (Default: ./docker-compose.yml)"
+      main-image-name:
+        type: string
+        description: "The name of the main image for checking if it exists with the given tag"
+        required: true
       image-tag:
         type: string
-        default: latest
-        description: "Tag of the Docker images to deploy (Default: latest)"
+        description: "Image tag to deploy (default: pr-<number> if PR exists, latest for default branch)"
       env-vars:
         type: string
         description: "Additional environment variables in KEY=VALUE format, separated by newlines"
         required: false
 
 jobs:
+  prepare-deploy:
+    runs-on: ubuntu-latest
+    environment: Dev
+    outputs:
+      image-tag-to-deploy: ${{ steps.retrieve-image-tag.outputs.image-tag-to-deploy }}
+    
+    steps:
+      - name: Retrieve image tag to deploy
+        id: retrieve-image-tag
+        run: |
+          if [ -n "${{ inputs.image-tag }}" ]; then
+            echo "image-tag-to-deploy=${{ inputs.image-tag }}" >> $GITHUB_OUTPUT
+            exit 0
+          fi
+
+          REF=$(echo "${{ github.event.ref }}" | sed -n 's#^refs/heads/##p')
+          if [ "$REF" = "${{ github.event.repository.default_branch }}" ]; then
+            echo "image-tag-to-deploy=latest" >> $GITHUB_OUTPUT
+          fi
+
+          PULLS=$(curl -s -H "Authorization: Bearer ${{ secrets.GITHUB_TOKEN }}" "https://api.github.com/repos/${{ github.repository }}/pulls?head=${{ github.repository_owner }}:${REF}")
+          PR_NUMBER=$(echo "$PULLS" | jq -r '.[0].number')
+
+          if [ -z "$PR_NUMBER" ]; then
+            echo "No PR found for branch $REF."
+            exit 1
+          else
+            echo "PR #$PR_NUMBER found for branch $REF."
+            echo "image-tag-to-deploy=pr-$PR_NUMBER" >> $GITHUB_OUTPUT
+          fi
+
+      - name: Check if image exists
+        run: |
+          IMAGE_NAME="${{ inputs.main-image-name }}"
+          IMAGE_TAG="${{ steps.retrieve-image-tag.outputs.image-tag-to-deploy }}"
+
+          ENCODED_TOKEN=$(echo -n "${{ secrets.GITHUB_TOKEN }}" | base64)
+          TAG_EXISTS=$(curl -s -H "Authorization: Bearer ${ENCODED_TOKEN}" \
+            https://ghcr.io/v2/${IMAGE_NAME}/tags/list \
+            | jq -r --arg TAG "${IMAGE_TAG}" '.tags[] | select(. == $TAG)')
+          
+          if [ -z "$TAG_EXISTS" ]; then
+            echo "Image ${IMAGE_NAME}:${IMAGE_TAG} does not exist."
+            exit 1
+          else
+            echo "Image ${IMAGE_NAME}:${IMAGE_TAG} exists."
+          fi
+
   deploy:
+    needs: prepare-deploy
     runs-on: ubuntu-latest
     environment: 
       name: ${{ inputs.environment }}
     steps:
-      - name: Checkout Repository
+      - name: Checkout repository
         uses: actions/checkout@v4
 
-      - name: SSH to VM and Execute Docker-Compose Down (if exists)
+      - name: SSH to VM and execute docker compose down (if exists)
         uses: appleboy/ssh-action@v1.0.3
         with:
           host: ${{ vars.VM_HOST }}
@@ -49,7 +101,7 @@ jobs:
             # Check if docker-compose.prod.yml exists
             if [ -f "$COMPOSE_FILE" ]; then
               echo "$COMPOSE_FILE found."
-              
+          
               # Check if .env exists
               if [ -f ".env" ]; then
                 docker compose -f "$COMPOSE_FILE" --env-file=".env" down --remove-orphans --rmi all
@@ -60,7 +112,7 @@ jobs:
               echo "$COMPOSE_FILE does not exist. Skipping docker compose down."
             fi
 
-      - name: Copy Docker Compose File to VM Host
+      - name: Copy docker compose file to VM host
         uses: appleboy/scp-action@v0.1.7
         with:
           host: ${{ vars.VM_HOST }}
@@ -73,7 +125,7 @@ jobs:
           source: ${{ inputs.docker-compose-file }}
           target: /home/${{ vars.VM_USERNAME }}
 
-      - name: SSH to VM and Create .env File
+      - name: SSH to VM and create .env file
         uses: appleboy/ssh-action@v1.0.3
         with:
           host: ${{ vars.VM_HOST }}
@@ -87,12 +139,12 @@ jobs:
             touch .env
 
             echo "ENVIRONMENT=${{ inputs.environment }}" > .env
-            echo "IMAGE_TAG=${{ inputs.image-tag }}" >> .env
+            echo "IMAGE_TAG=${{ needs.prepare-deploy.outputs.image-tag-to-deploy }}" >> .env
             if [ "${{ inputs.env-vars }}" != "" ]; then
               echo "${{ inputs.env-vars }}" >> .env
             fi
 
-      - name: SSH to VM and Execute Docker Compose Up
+      - name: SSH to VM and execute docker compose up
         uses: appleboy/ssh-action@v1.0.3
         with:
           host: ${{ vars.VM_HOST }}
diff --git a/docker-compose.prod.yml b/docker-compose.prod.yml
index 54ac0cba..90b8ff7b 100644
--- a/docker-compose.prod.yml
+++ b/docker-compose.prod.yml
@@ -1,5 +1,3 @@
-version: '3.8'
-
 services:
   redis:
     image: redis/redis-stack-server:7.4.0-v1
@@ -22,6 +20,8 @@ services:
       - APOLLON_REDIS_URL=redis://apollon-redis:6379
       - APOLLON_REDIS_DIAGRAM_TTL=${APOLLON_REDIS_DIAGRAM_TTL}
       - DEPLOYMENT_URL=${DEPLOYMENT_URL}
+    volumes:
+      - /opt/apollon/diagrams:/app/diagrams
     restart: unless-stopped
     ports:
       - "8080:8080"
diff --git a/docker-compose.yml b/docker-compose.yml
index 92b0edc4..6bc6114e 100644
--- a/docker-compose.yml
+++ b/docker-compose.yml
@@ -20,6 +20,8 @@ services:
       - APOLLON_REDIS_URL=redis://apollon_redis:6379
       - APOLLON_REDIS_DIAGRAM_TTL=${APOLLON_REDIS_DIAGRAM_TTL}
       - DEPLOYMENT_URL=${DEPLOYMENT_URL}
+    volumes:
+      - ./diagrams:/app/diagrams
     restart: always
     networks:
       - apollon_network