i let Firefox migrate my v18.0.2 to v19. I want to restore to v18 because PDF access is too slow on v19. I don't know where to find v18 to install it again. By letting Firefox do migrations, I never actually download and save the versions. I have no idea where Firefox is saving them on my system.
hello, firefox 19 has introduced its own integrated pdf viewer - if you want to switch back to the plugin you've used before to view pdfs just go to firefox options > applications & define the default action for the portable document format (pdf).