pin xcode 7

Pin? Could you elaborate a little what you mean?

for size classes like you can do in xcode 6

What do you mean by pin? Read the whole size class docs but still don't know what you mean.

@DW_APPs If you not asking how to do this programatically, but rather using Interface Builder's Pin control, please ask your question in the appropriate forum (this is a Swift forum).

There is info in the documentation for XCode you can get to by going to the Help menu and choosing Documentation and API Reference

In the pane on the left, choose XCode 7 Documentation > XCode > IDE's > Guides > AutoLayout Help

Or, the online version:

https://developer.apple.com/library/prerelease/ios/recipes/xcode_help-IB_auto_layout/chapters/UnderstandingAutolayout.html

Specifically:

https://developer.apple.com/library/prerelease/ios/recipes/xcode_help-IB_auto_layout/chapters/pin-constraints.html#//apple_ref/doc/uid/TP40014226-CH28-SW1

Ah thanks. So pin means the "add new constraits" button.

But what changed there? It works just as in Xcode 6.

I don't know? Maybe the op's project had issues being imported into 7 (or is an old project that predates the feature) and doesn't have auto layout turned on?