Why no Reader plugin for Vista using Firefox

Hello jimg56027510. I'm not an Adobe employee, but like you I'm still using Vista. I regret to inform you that the last Adobe Reader product that officially supported Vista was Reader X, and that support for Reader X ended more than a year ago: End of support for Acrobat X and Reader X . You cannot update to the latest Adobe Acrobat Reader DC product because it is incompatible with Vista. Between Reader X and Reader DC was Reader XI, which never officially supported Vista but does officially support Server 2008, which is the server version of Vista: System requirements for Adobe Reader—older versions (XI, X, 9) . Some people running Vista including myself have found that Reader XI works quite well on Vista, with the notable exception that update patches must be applied manually. My Adobe Reader XI is patched to the current 11.0.18 version. (The last version to support XP was 11.0.08, so I've got them beat.) Here's a Bleeping Computer thread where various PDF options for Vista were discussed: http://www.bleepingcomputer.com/forums/t/624264/adobe-acrobat-reader-for-vista/ .

If Firefox still allows you to use your outdated Adobe Reader plugin, then one option is to do nothing. BTW I'm using Firefox 50.1.0, and I don't even see that pesky plugin checker anymore. Mozilla reportedly plans to end support for all NPAPI plugins except Flash Player before long anyway. I wonder if you have heard the news that Firefox is planning to end support for Windows XP and Vista: https://blog.mozilla.org/futurereleases/2016/12/23/firefox-support-for-xp-and-vista/ .