What is the most stable rhomobile version that supports Xcode 7.0.1?
A future one!

Like Lucy (from the Peanuts comic strip), Apple moves the football every time they make a major-version release of XCode, and it requires a major rewrite of the Rhodes build scripts. So, you wind-up kicking air.

Tau Platform purportedly support XCode 7, at least according to checkin comments. It's forked from Rhodes 5.2.2, and doesn't seem to have much change other than that at this point. But if you need RhoElements, I think you are out of luck, as that is proprietary to RhoMobile, and I don't know if supported on Tau Platform (even if you have a Rhodes license).

I don't want to spam about the "competition" (much! ) but I do want to encourage sharing back and forth of the open-source bits. Zebra could adopt this build code, and perhaps already has plans to, I dunno. (And I see Tau borrowed much of this code from the Chromium Project, of all places... In the past, some build code has been borrowed from Cordova. Ain't open-source wonderful! Kudos to Zebra for keeping it open!)

I haven't tried it, as I don't have a current need to build with XCode7/iOS9, as current projects target iOS8. (So I don't even have XCode7 installed...)

You can build with XCode6 for iOS 8.4 and it will run on iOS9, though. If you need to release for App Store, not sure when the window will close for apps built for iOS8. Probably quite some time yet.

I need to do some testing next week to see what issues apps face if built for iOS8 and run on iOS9. I know there are some UI formatting issues (if using jQuery Mobile) that appear easily solved with some judicious application of width:100% CSS. (e.g. some elements that one would expect to be full-width no longer are...) looks like there were some subtle UIWebView CSS cascade changes. And a big issue if you use window.history or jQuery Mobile "back" mechanism. (Thankfully, my apps don't, so navigation hasn't been broken...)

FWIW, here's the commit (or at least the major one) that adds XCode 7 support to Tau. As you can see, it is a lot of change. I'm not sure that this is the only related change. Posting this just to show the magnitude of the change, and that I don't think one should expect current versions to work. (Though somehow, I think some have purported success?)

Support XCode 7.0 and iOS 9.0 · tauplatform/tau@f80ec32 · GitHub

Hi
Rhomobile officially doesnt support Xcode7 and IOS 9, The support will be available in upcoming release.(in november) .
However  You can still build RMS project(using version  5.1.1 /5.2.2) with Xcode 7 using the following changes.

1.Clean existing iphone builds by running rake clean:iphone in terminal
2.Create an Xcode project by running rake build:iphone:setup_xcode_project in terminal
3: Info.plist changes (located in project folder(app_folder/project/iphone/Info.plist)) .

NSAppTransportSecurity

 
        NSAllowsArbitraryLoads
 

4: open the code project and disable bitcode in build settings.

Find the screenshot available at .
https://zebra.box.com/shared/static/9kuh35s9vox7c4azveb4csup8i4k6rgm.png
https://zebra.box.com/shared/static/kqi88mvdw2nk6pk6j3qt1q2g85xnbhce.png

Note: With these changes you can launch application on devices not on ios9 simulator