<html><head><meta http-equiv="Content-Type" content="text/html charset=utf-8"></head><body style="word-wrap: break-word; -webkit-nbsp-mode: space; -webkit-line-break: after-white-space;" class=""><div class="">Hi everyone,<div class=""><br class=""></div><div class="">Something I’ve come across in iOS 11 is that you can’t override properties that are only available on iOS 11 when deploying with a deployment target less than the current target.</div><div class=""><br class=""></div><div class="">For example the following code is invalid:</div><div class=""><br class=""></div><div class=""><div style="margin: 0px; font-size: 11px; line-height: normal; color: rgb(112, 61, 170); background-color: rgb(255, 255, 255);" class=""><span style="color: rgb(186, 45, 162);" class="">extension</span><span style="color: rgb(0, 0, 0);" class=""> </span>UIViewController<span style="color: rgb(0, 0, 0);" class=""> {</span></div><div style="margin: 0px; font-size: 11px; line-height: normal; background-color: rgb(255, 255, 255); min-height: 13px;" class=""> <br class="webkit-block-placeholder"></div><div style="margin: 0px; font-size: 11px; line-height: normal; background-color: rgb(255, 255, 255);" class=""> <span style="color: rgb(186, 45, 162);" class="">@available</span>(<span style="color: rgb(186, 45, 162);" class="">iOS</span>, introduced: <span style="color: rgb(39, 42, 216);" class="">11.0</span>)</div><div style="margin: 0px; font-size: 11px; line-height: normal; background-color: rgb(255, 255, 255);" class=""> <span style="color: rgb(186, 45, 162);" class="">open</span> <span style="color: rgb(186, 45, 162);" class="">override</span> <span style="color: rgb(186, 45, 162);" class="">var</span> <span style="text-decoration: underline;" class="">a</span>dditionalSafeAreaInsets: <span style="color: rgb(112, 61, 170);" class="">UIEdgeInsets</span> {</div><div style="margin: 0px; font-size: 11px; line-height: normal; background-color: rgb(255, 255, 255);" class=""> <span style="color: rgb(186, 45, 162);" class="">didSet</span> {</div><div style="margin: 0px; font-size: 11px; line-height: normal; color: rgb(0, 132, 0); background-color: rgb(255, 255, 255);" class=""><span style="color: rgb(0, 0, 0);" class=""> </span>// Do work here only relevant to iOS 11</div><div style="margin: 0px; font-size: 11px; line-height: normal; background-color: rgb(255, 255, 255);" class=""> }</div><div style="margin: 0px; font-size: 11px; line-height: normal; background-color: rgb(255, 255, 255);" class=""> } </div><div style="margin: 0px; font-size: 11px; line-height: normal; background-color: rgb(255, 255, 255);" class="">}</div></div><div class=""><br class=""></div><div class="">This would be easily overridden in Obj-C, but I can’t do it in Swift. Is there any reason why this limitation exists?</div></div><div class=""><br class=""></div><div class="">Thanks,</div><div class=""><br class=""></div><div class="">Rod</div></body></html>