How to install ios5 on ipad2

because its not on the latest iOS i think the iPad 2 goes up to iOS 8 the apps are on iOS 11had the same problem i had to buy a up to date ipad

I don't think that you can update an iPad of any type to a specific iOS version. When you chose to update, it usually auto-updates to the latest version of the iOS that is compatible with your device.

There are multiple ways to update iPad. The easiest way is to do that in the Settings app. Follow below steps to reach the aim.

1. If a pop-up panel tells you that iTouch latest version is available, you can then tap on the button of "Install Now" to begin to update to apple iOS latest version.
2. You can also manually check out if the apple iOS latest version is available now. Now you can follow the steps shown below to have a try.
a) Connect your iPod to good Wi-Fi connection and make sure your iPod storage is enough and the battery is able to support the iPod update.
b) Click on "Settings > General > Software Update" successively.
c) When your iPod has detected an apple iPod latest version, you can click on the button of "Install Now". If a dialog requires you to delete some apps temporarily because the new version needs more storage, you can click on "Continue" to uninstall the apps. If you click on "Cancel" button, your apps will not be uninstalled.
d) After that, iPod will begin downloading and installing the apple iOS latest version in no time. Wait until the update is finished.

The process to update to iTouch latest version is not hard at all. Actually, before the update, you can manage your iPod files to make some room for the new version or to make the process much smoother. The next two parts will instruct you how to manage files via iTunes or iTransfer in detail.

For more methods, check: How to Update iPod to the Latest iOS Version

You may have too many apps, and you may have too many videos, photos, etc... People don't realize how much memory is eaten up by apps. They not only take up space when installed, they also take up tons of space when they store data. Best bet is to eliminate all apps that you don't really use, and then go into your settings to clear all "cache" memory that the apps are using up. Also, the best way to speed up an iPad is to do a factory reset which deletes _everything_, and then go and install fresh new versions of all apps that you _regularly_ use. Note: A fully "updated" app is not the same as an installation of the "latest version" of an app. I realize what a big deal totally reinstalling everything is, but you'd be amazed at the "new iPad" you wind up with. // Note: Using "cloud" to reinstall everything defeats the purpose. You want _new_ fresh latest versions of all apps. You can use cloud to restore _only_ your files, such as photos, music, etc. But be careful about the settings. Most people have their cloud settings set for "full restore" which (as I stated) defeats the entire purpose of a "factory reset."

- meanwhile you may download the iOS 8.1.2 which is good and some Apps require it....
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There are two ways to upgrade the iOS version of your iPad
- via connecting the device to iTunes on a computer
- or directly from within the device, but only since iOS 5, it is possible to upgrade the iOS version without the need to connect the iOS device to a computer (over-the-air update)
just go to: settings - general - software update

Plug your iPad 2 into the device where you run iTunes. In iTunes, select the iPad in the left column, then select the Summary panel. At the upper right, continue by downloading and installing the latest version of iOS that will run on that device. We use iOS 7 on our iPad 2 - and it runs very nicely.

For the iPad first generation (A1219) to update is only possible with connecting the device to iTunes on a computer.
- this model supports only iOS 5 - NO iOS 6/7/8

probably it helps to update your system to the newest
iOS 8.1.2
- there might be a compability conflict between the app and iOS version....

How to Install iOS 8 1 2 On iPhone iPad and iPod Touch

You can't get back the original OS.
Apple doesn't allow that.
Apple only allows (or forces) you to upgrade to the latest iOS version for your specific device.

i would suggest backing up your device to iTunes in your computer, the updating the iOS on your iPad
, or doing a factory reset where your iPad will be reset to the way it was when you got it ... though the iOS will probably be updated, then using iTunes to recover your files from your computer to your iPad.