Problem developing App using Xcode I am currently developing an application in Mac OS X Yosemite. The Ipad which is being used to run the application runs on iOS 9.3 which requires Xcode 7.3 which can only be installed in OS X EI Capitan. Is there any way to resolve this issue with out upgrading it to Capitan?

OS X Yosemite is not supporting XCode 7.3

Also is it recommended to downgrade ipad to 9.2.1 
?? Will it work properly again?
Thank you.
In short, Apple want you to play their game - if you're going to participate, you have to play by their current rules, not last season's.
So, no, if you want the latest Xcode you need the OS that supports it.

Your workaround would be to set up a dual boot or VM.

Your second question has a similar answer, well covered here - Can I install any iOS version I wish by picking and choosing which firmware to restore?

You might have a week or so to downgrade before it's blocked, though you'll have to set up as new &amp; lose any backup.