Due to Adobe’s subscription push, many have switched to lighter, more secure alternatives that still support old hardware:
Support for Adobe Reader XI followed the standard Adobe lifecycle: adobe reader xi version 11.0.23
By the time Adobe reached 11.0.23, they had already released over two dozen patches fixing everything from memory corruption bugs (CVE-2017-11237) to privilege escalation vulnerabilities. Version 11.0.23 was rolled out on as an "out-of-cycle" security update to patch CVE-2018-4878—a critical Flash Player vulnerability that allowed remote code execution via malicious Flash files embedded in PDFs. Due to Adobe’s subscription push, many have switched