If you want to manually download updates and new versions, you should only get them from the official Adobe Acrobat website.
Downloading from other sites can leave your PC open to infection.
Hackers, along with malicious programs or viruses, find weaknesses in software (called vulnerabilities) that they exploit to access your computer, smartphone or tablet.
Installing updates fixes these vulnerabilities and helps keep you secure.
Apple generally provides updates for the latest and immediately previous versions of their operating system, but not for older versions.
For detailed information visit the Apple website: Anti-virus software requires regular signature updates to remain effective.