diff -urp dist/bin/yarn.js patched/bin/yarn.js
--- dist/bin/yarn.js	2017-01-30 14:11:29.000000000 +0000
+++ patched/bin/yarn.js	2017-02-01 02:41:32.000000000 +0000
@@ -16,17 +16,14 @@ var _err;
 if (semver.satisfies(ver, '>=5.0.0')) {
   possibles.push('../updates/current/lib/cli/index.js');
   possibles.push('../lib/cli/index.js');
-} else if (semver.satisfies(ver, '>=4.0.0')) {
-  possibles.push('../updates/current/lib-legacy/cli/index.js');
-  possibles.push('../lib-legacy/cli/index.js');
 } else {
-  console.log(require('chalk').red('Node version ' + ver + ' is not supported, please use Node.js 4.0 or higher.'));
+  console.log(require('chalk').red('Node version ' + ver + ' is not supported, please use Node.js 5.0 or higher.'));
   process.exit(1);
 }
 
 // ensure cache directory exists
 var mkdirp = require('mkdirp');
-var constants = require('../lib-legacy/constants');
+var constants = require('../lib/constants');
 mkdirp.sync(constants.MODULE_CACHE_DIRECTORY);
 
 // init roadrunner