# Tweet by [@keefmoon](http://twitter.com/keefmoon) on 2017-06-04 20:40:16 > [!INFO] Archived from [original tweet](http://twitter.com/keefmoon/status/871466654898769920) RT @nicklockwood: I converted my 3 most complex Swift 3 libs to build w/ Swift 4 in 20 mins, & the changes are 100% b/w compatible. So much…