title: PDF compatibility levels
body: <p>I was wondering what peoples opinions are on what compatibility level you set your PDFs. The lower you decided the higher the file size, so I assume it's a balance between optimizing the file size and supporting older adobe versions. Does anyone know the percentages of users use below version 8?</p>
  
  <p>Reference
  <a href="https://acrobatusers.com/tutorials/understanding-pdf-compatibility-levels" rel="nofollow">https://acrobatusers.com/tutorials/understanding-pdf-compatibility-levels</a></p>