diff --git a/package.json b/package.json
index fd610922f..51b9e11df 100644
--- a/package.json
+++ b/package.json
@@ -72,7 +72,7 @@
     "eslint": "^4.16.0",
     "eslint-config-prettier": "^2.9.0",
     "eslint-plugin-flowtype": "^2.41.0",
-    "flow-bin": "^0.69.0",
+    "flow-bin": "^0.71.0",
     "fs-extra": "^5.0.0",
     "husky": "^0.14.3",
     "jest": "^22.1.4",
diff --git a/src/commands/shared_options.js b/src/commands/shared_options.js
index 39cc9039d..c835e28a6 100644
--- a/src/commands/shared_options.js
+++ b/src/commands/shared_options.js
@@ -34,13 +34,13 @@ module.exports.sharedInputOptions = {
       "additional extensions to include in require() and import's search algorithm." +
       'For instance, adding .es5 would allow require("adder") to find "adder.es5"',
     // Ensure that the value is an array
-    coerce: (value: string | Array<string>) => [].concat(value),
+    coerce: (value: string | Array<string>): Array<string> => [].concat(value),
     alias: 're'
   },
   'parse-extension': {
     describe: 'additional extensions to parse as source code.',
     // Ensure that the value is an array
-    coerce: (value: string | Array<string>) => [].concat(value),
+    coerce: (value: string | Array<string>): Array<string> => [].concat(value),
     alias: 'pe'
   },
   private: {
diff --git a/src/output/util/format_type.js b/src/output/util/format_type.js
index 1be977525..91ef57bd1 100644
--- a/src/output/util/format_type.js
+++ b/src/output/util/format_type.js
@@ -81,7 +81,7 @@ function commaList(getHref, items, start, end, sep) {
  * @param {boolean} prefix string to put after the type comment
  * @returns {Array<Object>} suffixed and potentially prefixed type
  */
-function decorate(formatted, str, prefix) {
+function decorate(formatted, str, prefix): Array<Object> {
   if (prefix) {
     return [t(str)].concat(formatted);
   }
@@ -100,7 +100,7 @@ function decorate(formatted, str, prefix) {
  * formatType({ type: 'NameExpression', name: 'String' })[0].url
  * // => 'https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/String'
  */
-function formatType(getHref: Function, node: ?Object) {
+function formatType(getHref: Function, node: ?Object): Array<Object> {
   let result = [];
 
   if (!node) {
diff --git a/src/sort.js b/src/sort.js
index ee1344576..6b882bb94 100644
--- a/src/sort.js
+++ b/src/sort.js
@@ -14,7 +14,10 @@ const fs = require('fs');
  * @returns {number} sorting value
  * @private
  */
-module.exports = function sortDocs(comments: Array<Comment>, options: Object) {
+module.exports = function sortDocs(
+  comments: Array<Comment>,
+  options: Object
+): Array<Comment> {
   if (!options || !options.toc) {
     return sortComments(comments, options && options.sortOrder);
   }
@@ -124,7 +127,10 @@ function compareCommentsBySourceLocation(a: Comment, b: Comment): number {
   return a.context.sortKey.localeCompare(b.context.sortKey);
 }
 
-function sortComments(comments: Array<Comment>, sortOrder: string) {
+function sortComments(
+  comments: Array<Comment>,
+  sortOrder: string
+): Array<Comment> {
   return comments.sort(
     sortOrder === 'alpha'
       ? compareCommentsByName
diff --git a/yarn.lock b/yarn.lock
index df0106547..31056e5d9 100644
--- a/yarn.lock
+++ b/yarn.lock
@@ -2424,9 +2424,9 @@ flat-cache@^1.2.1:
     graceful-fs "^4.1.2"
     write "^0.2.1"
 
-flow-bin@^0.69.0:
-  version "0.69.0"
-  resolved "https://registry.yarnpkg.com/flow-bin/-/flow-bin-0.69.0.tgz#053159a684a6051fcbf0b71a2eb19a9679082da6"
+flow-bin@^0.71.0:
+  version "0.71.0"
+  resolved "https://registry.yarnpkg.com/flow-bin/-/flow-bin-0.71.0.tgz#fd1b27a6458c3ebaa5cb811853182ed631918b70"
 
 flush-write-stream@^1.0.2:
   version "1.0.2"