I ran into this issue when deploying patches for the last couple of versions. For whatever reason Adobe does not seem to want to put the latest ones up on the main Acrobat Reader DC pages - I had to go to this Adobe Devnet page to find the newest installers. Seems they consider them "optional" - https://www.adobe.com/devnet-docs/acrobatetk/tools/ReleaseNotesDC/index.html
