Let's encourage Node.6+. FWIW, this flag is mostly ignored.

cjbj · cjbj · commit 2cdaba934d47 · 2018-11-15T16:31:12.000+11:00
diff --git a/package.json b/package.json
@@ -42,7 +42,7 @@
     "posttest": "node test/opts/version.js"
   },
   "engines": {
-    "node": ">=4"
+    "node": ">=6"
   },
   "maintainers": [
     {
diff --git a/package/package.json b/package/package.json
@@ -40,7 +40,7 @@
     "posttest": "node test/opts/version.js"
   },
   "engines": {
-    "node": ">=4"
+    "node": ">=6"
   },
   "maintainers": [
     {

Original file line number	Diff line number	Diff line change
`@@ -42,7 +42,7 @@`
`42`	`42`	`"posttest": "node test/opts/version.js"`
`43`	`43`	`},`
`44`	`44`	`"engines": {`
`45`		`- "node": ">=4"`
	`45`	`+ "node": ">=6"`
`46`	`46`	`},`
`47`	`47`	`"maintainers": [`
`48`	`48`	`{`
Original file line number	Diff line number	Diff line change
`@@ -40,7 +40,7 @@`
`40`	`40`	`"posttest": "node test/opts/version.js"`
`41`	`41`	`},`
`42`	`42`	`"engines": {`
`43`		`- "node": ">=4"`
	`43`	`+ "node": ">=6"`
`44`	`44`	`},`
`45`	`45`	`"maintainers": [`
`46`	`46`	`{`