Older generation of iPad and software

Do older generation iPads update to the latest operating systems and browsers availble? I can't find a list of iPad's and their most recent associated OS or browser versions which is what prompted me to ask. I am not a apple user normally so I have very limited knowledge on these products. I am trying to find supported software on each generation of iPad's and iPhones. For instance, some pc's are only able to run up to Windows XP SP3 and IE9 or later (just an example - dont rake me over the coals if this is not exactly true). 😉 Thanks in advance for helping me understand this while making some purchasing decisions.