diff --git a/gulpfile.js b/gulpfile.js
index 94e1734..6a0fefa 100644
--- a/gulpfile.js
+++ b/gulpfile.js
@@ -2,21 +2,21 @@
 
 // Define variables.
 const autoprefixer = require("autoprefixer");
-const browserSync  = require("browser-sync").create();
-const cleancss     = require("gulp-clean-css");
-const concat       = require("gulp-concat");
-const del          = require("del");
-const gulp         = require("gulp");
-const gutil        = require("gulp-util");
-const imagemin     = require("gulp-imagemin");
-const notify       = require("gulp-notify");
-const postcss      = require("gulp-postcss");
-const rename       = require("gulp-rename");
-const run          = require("gulp-run");
-const runSequence  = require("run-sequence");
-const sass         = require("gulp-ruby-sass");
-const sprockets    = require("gulp-sprockets");
-const uglify       = require("gulp-uglify");
+const browserSync = require("browser-sync").create();
+const cleancss = require("gulp-clean-css");
+const concat = require("gulp-concat");
+const del = require("del");
+const gulp = require("gulp");
+const gutil = require("gulp-util");
+const imagemin = require("gulp-imagemin");
+const notify = require("gulp-notify");
+const postcss = require("gulp-postcss");
+const rename = require("gulp-rename");
+const run = require("gulp-run");
+const runSequence = require("run-sequence");
+const sass = require("gulp-ruby-sass");
+const sprockets = require("gulp-sprockets");
+const uglify = require("gulp-uglify");
 
 // Include paths file.
 const paths = require("./_assets/gulp_config/paths");
@@ -25,12 +25,12 @@ sprockets.default.declare(paths.sprocketsDirs, paths.siteJsFiles);
 
 // Uses Sass compiler to process styles, adds vendor prefixes, minifies, then
 // outputs file to the appropriate location.
-gulp.task("build:styles:main", function() {
+gulp.task("build:styles:main", function () {
     return sass(paths.sassFiles + "/main.scss", {
         style: "compressed",
         trace: true,
         loadPath: [paths.sassFiles]
-    }).pipe(postcss([ autoprefixer({ browsers: ["last 2 versions"] }) ]))
+    }).pipe(postcss([autoprefixer({browsers: ["last 2 versions"]})]))
         .pipe(cleancss())
         .pipe(gulp.dest(paths.jekyllCssFiles))
         .pipe(gulp.dest(paths.siteCssFiles))
@@ -39,21 +39,21 @@ gulp.task("build:styles:main", function() {
 });
 
 // Processes critical CSS, to be included in head.html.
-gulp.task("build:styles:critical", function() {
+gulp.task("build:styles:critical", function () {
     return sass(paths.sassFiles + "/critical.scss", {
         style: "compressed",
         trace: true,
         loadPath: [paths.sassFiles]
-    }).pipe(postcss([ autoprefixer({ browsers: ["last 2 versions"] }) ]))
+    }).pipe(postcss([autoprefixer({browsers: ["last 2 versions"]})]))
         .pipe(cleancss())
         .pipe(gulp.dest("_includes"))
         .on("error", gutil.log);
 });
 
 // Builds all styles.
-gulp.task("build:styles", ["build:styles:main", "build:styles:critical"]);
+gulp.task("build:styles", gulp.series("build:styles:main", "build:styles:critical"));
 
-gulp.task("clean:styles", function(callback) {
+gulp.task("clean:styles", function (callback) {
     del([paths.jekyllCssFiles + "main.css",
         paths.siteCssFiles + "main.css",
         "_includes/critical.css"
@@ -63,7 +63,7 @@ gulp.task("clean:styles", function(callback) {
 
 // Concatenates and uglifies global JS files and outputs result to the
 // appropriate location.
-gulp.task("build:scripts:global", function() {
+gulp.task("build:scripts:global", function () {
     return gulp.src([
         paths.jsFiles + "/global/lib" + paths.jsPattern,
         paths.jsFiles + "/global/*.js"
@@ -76,14 +76,14 @@ gulp.task("build:scripts:global", function() {
         .on("error", gutil.log);
 });
 
-gulp.task("clean:scripts", function(callback) {
+gulp.task("clean:scripts", function (callback) {
     del([paths.jekyllJsFiles + "main.js", paths.siteJsFiles + "main.js"]);
     callback();
 });
 
 // Concatenates and uglifies leaflet JS files and outputs result to the
 // appropriate location.
-gulp.task("build:scripts:leaflet", function() {
+gulp.task("build:scripts:leaflet", function () {
     return gulp.src([
         paths.jsFiles + "/leaflet/leaflet.js",
         paths.jsFiles + "/leaflet/leaflet-providers.js"
@@ -95,16 +95,16 @@ gulp.task("build:scripts:leaflet", function() {
         .on("error", gutil.log);
 });
 
-gulp.task("clean:scripts:leaflet", function(callback) {
+gulp.task("clean:scripts:leaflet", function (callback) {
     del([paths.jekyllJsFiles + "leaflet.js", paths.siteJsFiles + "leaflet.js"]);
     callback();
 });
 
 // Builds all scripts.
-gulp.task("build:scripts", ["build:scripts:global", "build:scripts:leaflet"]);
+gulp.task("build:scripts", gulp.series("build:scripts:global", "build:scripts:leaflet"));
 
 // Optimizes and copies image files.
-gulp.task("build:images", function() {
+gulp.task("build:images", function () {
     return gulp.src(paths.imageFilesGlob)
         .pipe(imagemin())
         .pipe(gulp.dest(paths.jekyllImageFiles))
@@ -112,13 +112,13 @@ gulp.task("build:images", function() {
         .pipe(browserSync.stream());
 });
 
-gulp.task("clean:images", function(callback) {
+gulp.task("clean:images", function (callback) {
     del([paths.jekyllImageFiles, paths.siteImageFiles]);
     callback();
 });
 
 // Runs jekyll build command.
-gulp.task("build:jekyll", function() {
+gulp.task("build:jekyll", function () {
     var shellCommand = "bundle exec jekyll build --config _config.yml";
 
     return gulp.src("")
@@ -127,7 +127,7 @@ gulp.task("build:jekyll", function() {
 });
 
 // Runs jekyll build command using test config.
-gulp.task("build:jekyll:test", function() {
+gulp.task("build:jekyll:test", function () {
     var shellCommand = "bundle exec jekyll build --config _config.yml,_config.test.yml";
 
     return gulp.src("")
@@ -136,7 +136,7 @@ gulp.task("build:jekyll:test", function() {
 });
 
 // Runs jekyll build command using local config.
-gulp.task("build:jekyll:local", function() {
+gulp.task("build:jekyll:local", function () {
     var shellCommand = "bundle exec jekyll build --config _config.yml,_config.test.yml,_config.dev.yml";
 
     return gulp.src("")
@@ -145,58 +145,58 @@ gulp.task("build:jekyll:local", function() {
 });
 
 // Deletes the entire _site directory.
-gulp.task("clean:jekyll", function(callback) {
+gulp.task("clean:jekyll", function (callback) {
     del(["_site"]);
     callback();
 });
 
-gulp.task("clean", ["clean:jekyll",
+gulp.task("clean", gulp.series("clean:jekyll",
     "clean:images",
     "clean:scripts",
-    "clean:styles"]);
+    "clean:styles"));
 
 // Builds site anew.
-gulp.task("build", function(callback) {
-    runSequence("clean",
-        ["build:scripts", "build:images", "build:styles"],
-        "build:jekyll",
-        callback);
+gulp.task("build", function (callback) {
+    gulp.series("clean",
+        gulp.series("build:scripts", "build:images", "build:styles"),
+        "build:jekyll");
+    callback();
 });
 
 // Builds site anew using test config.
-gulp.task("build:test", function(callback) {
-    runSequence("clean",
-        ["build:scripts", "build:images", "build:styles"],
-        "build:jekyll:test",
-        callback);
+gulp.task("build:test", function (callback) {
+    gulp.series("clean",
+        gulp.series("build:scripts", "build:images", "build:styles"),
+        "build:jekyll:test");
+    callback();
 });
 
 // Builds site anew using local config.
-gulp.task("build:local", function(callback) {
-    runSequence("clean",
-        ["build:scripts", "build:images", "build:styles"],
-        "build:jekyll:local",
-        callback);
+gulp.task("build:local", function (callback) {
+    gulp.series("clean",
+        gulp.series("build:scripts", "build:images", "build:styles"),
+        "build:jekyll:local");
+    callback();
 });
 
 // Default Task: builds site.
-gulp.task("default", ["build"]);
+gulp.task("default", gulp.series("build"));
 
 // Special tasks for building and then reloading BrowserSync.
-gulp.task("build:jekyll:watch", ["build:jekyll:local"], function(callback) {
+gulp.task("build:jekyll:watch", gulp.series("build:jekyll:local", function (callback) {
     browserSync.reload();
     callback();
-});
+}));
 
-gulp.task("build:scripts:watch", ["build:scripts"], function(callback) {
+gulp.task("build:scripts:watch", gulp.series("build:scripts", function (callback) {
     browserSync.reload();
     callback();
-});
+}));
 
 // Static Server + watching files.
 // Note: passing anything besides hard-coded literal paths with globs doesn't
 // seem to work with gulp.watch().
-gulp.task("serve", ["build:local"], function() {
+gulp.task("serve", gulp.series("build:local", function () {
 
     browserSync.init({
         server: paths.siteDir,
@@ -207,43 +207,43 @@ gulp.task("serve", ["build:local"], function() {
     });
 
     // Watch site settings.
-    gulp.watch(["_config.yml"], ["build:jekyll:watch"]);
+    gulp.watch(["_config.yml"], gulp.series("build:jekyll:watch"));
 
     // Watch .scss files; changes are piped to browserSync.
-    gulp.watch("_assets/styles/**/*.scss", ["build:styles"]);
+    gulp.watch("_assets/styles/**/*.scss", gulp.series("build:styles"));
 
     // Watch .js files.
-    gulp.watch("_assets/js/**/*.js", ["build:scripts:watch"]);
+    gulp.watch("_assets/js/**/*.js", gulp.series("build:scripts:watch"));
 
     // Watch image files; changes are piped to browserSync.
-    gulp.watch("_assets/img/**/*", ["build:images"]);
+    gulp.watch("_assets/img/**/*", gulp.series("build:images"));
 
     // Watch posts.
-    gulp.watch("_posts/**/*.+(md|markdown|MD)", ["build:jekyll:watch"]);
+    gulp.watch("_posts/**/*.+(md|markdown|MD)", gulp.series("build:jekyll:watch"));
 
     // Watch drafts if --drafts flag was passed.
     if (module.exports.drafts) {
-        gulp.watch("_drafts/*.+(md|markdown|MD)", ["build:jekyll:watch"]);
+        gulp.watch("_drafts/*.+(md|markdown|MD)", gulp.series("build:jekyll:watch"));
     }
 
     // Watch html and markdown files.
-    gulp.watch(["**/*.+(html|md|markdown|MD)", "!_site/**/*.*"], ["build:jekyll:watch"]);
+    gulp.watch(["**/*.+(html|md|markdown|MD)", "!_site/**/*.*"], gulp.series("build:jekyll:watch"));
 
     // Watch RSS feed XML files.
-    gulp.watch("**.xml", ["build:jekyll:watch"]);
+    gulp.watch("**.xml", gulp.series("build:jekyll:watch"));
 
     // Watch data files.
-    gulp.watch("_data/**.*+(yml|yaml|csv|json)", ["build:jekyll:watch"]);
+    gulp.watch("_data/**.*+(yml|yaml|csv|json)", gulp.series("build:jekyll:watch"));
 
     // Watch favicon.png.
-    gulp.watch("favicon.png", ["build:jekyll:watch"]);
-});
+    gulp.watch("favicon.png", gulp.series("build:jekyll:watch"));
+}));
 
 // Updates Ruby gems
-gulp.task("update:bundle", function() {
+gulp.task("update:bundle", function () {
     return gulp.src("")
         .pipe(run("bundle install"))
         .pipe(run("bundle update"))
-        .pipe(notify({ message: "Bundle Update Complete" }))
+        .pipe(notify({message: "Bundle Update Complete"}))
         .on("error", gutil.log);
 });