title: What version(s) of iOS should my App support?
body: <blockquote>
  <p><em>NB: This question has been extensively edited to make it more relevant, for completeness the original question maintained at the end.</em></p>
  </blockquote>
  <h2>What version(s) of iOS should my App support?</h2>
  <p>When building a new iOS app what a strategies should one use to determine what versions of the operating system to support? What practical considerations are there in supporting legacy OS version. Are there any reliable statistics to support the business case of dropping legacy support?</p>
  <h2>Original Question</h2>
  <p>If I build a new iOS application, should I support iOS versions prior to 5.0, or is that not necessary anymore? Is there any reliable and up to date data on iOS 5.0 adoption rates?</p>