diff --git a/.travis.yml b/.travis.yml
index f3c856a..aea3f2a 100644
--- a/.travis.yml
+++ b/.travis.yml
@@ -1,40 +1,51 @@
-language: php
-
 sudo: false
+dist: trusty
+
+language: php
 
-php:
-    - 5.6
-    - 7.0
-    - 7.1
+notifications:
+  email:
+    on_success: never
+    on_failure: change
 
-env:
-    - WP_VERSION=nightly
-    - WP_VERSION=latest
-    - WP_VERSION=4.7
-    - WP_VERSION=4.6
+branches:
+  only:
+  - /.*/
 
 cache:
   directories:
+    - vendor
     - $HOME/.composer/cache
 
-before_install:
-  - composer self-update
-
-install:
-  - composer install --prefer-dist
+matrix:
+  include:
+    - php: 7.2
+      env: WP_VERSION=latest
+    - php: 7.2
+      env: WP_VERSION=4.9.10
+    - php: 7.0
+      env: WP_VERSION=latest
+    - php: 7.0
+      env: WP_VERSION=4.9.10
 
 before_script:
   - export PATH="$HOME/.composer/vendor/bin:$PATH"
   - |
-    if [[ ${TRAVIS_PHP_VERSION:0:2} == "7." ]]; then
-      composer global require "phpunit/phpunit=5.7.*"
+    if [ -f ~/.phpenv/versions/$(phpenv version-name)/etc/conf.d/xdebug.ini ]; then
+      phpenv config-rm xdebug.ini
     else
-      composer global require "phpunit/phpunit=4.8.*"
+      echo "xdebug.ini does not exist"
+    fi
+  - |
+    if [[ ! -z "$WP_VERSION" ]] ; then
+      bash bin/install-wp-tests.sh wordpress_test root '' localhost $WP_VERSION
+      composer global require "phpunit/phpunit=4.8.*|5.7.*"
+    fi
+  - |
+    if [[ "$WP_TRAVISCI" == "phpcs" ]] ; then
+      composer global require wp-coding-standards/wpcs
+      phpcs --config-set installed_paths $HOME/.composer/vendor/wp-coding-standards/wpcs
     fi
-
-  - git config --global user.email "travis-ci@codeclimate.com"
-  - git config --global user.name "Travis CI"
-  - bash bin/install-wp-tests.sh wordpress_test root '' localhost $WP_VERSION
 
 script:
   - |
@@ -42,10 +53,7 @@ script:
       phpunit
       WP_MULTISITE=1 phpunit
     fi
-
-after_script:
-  - ./bin/codeclimate.sh
-
-addons:
-  codeclimate:
-    repo_token: CODECLIMATE_REPO_TOKEN
\ No newline at end of file
+  - |
+    if [[ "$WP_TRAVISCI" == "phpcs" ]] ; then
+      phpcs
+    fi
diff --git a/admin/manager.php b/admin/manager.php
index a86db1f..a56fc50 100644
--- a/admin/manager.php
+++ b/admin/manager.php
@@ -415,6 +415,9 @@ public function save() {
 				// @todo notify user of error messages from WP_Error objects
 				$this->plugin->log( '%s - Errors encountered during navman save: %s', __METHOD__, print_r( $errors, true ) );
 			}
+
+			// Update the `last_changed` key value with the current time.
+			wp_cache_set( 'last_changed', microtime(), 'posts' );
 		}
 
 		return $saved;
diff --git a/bin/install-wp-tests.sh b/bin/install-wp-tests.sh
index 555b6ad..49e3f34 100755
--- a/bin/install-wp-tests.sh
+++ b/bin/install-wp-tests.sh
@@ -12,8 +12,10 @@ DB_HOST=${4-localhost}
 WP_VERSION=${5-latest}
 SKIP_DB_CREATE=${6-false}
 
-WP_TESTS_DIR=${WP_TESTS_DIR-/tmp/wordpress-tests-lib}
-WP_CORE_DIR=${WP_CORE_DIR-/tmp/wordpress/}
+TMPDIR=${TMPDIR-/tmp}
+TMPDIR=$(echo $TMPDIR | sed -e "s/\/$//")
+WP_TESTS_DIR=${WP_TESTS_DIR-$TMPDIR/wordpress-tests-lib}
+WP_CORE_DIR=${WP_CORE_DIR-$TMPDIR/wordpress/}
 
 download() {
     if [ `which curl` ]; then
@@ -23,8 +25,15 @@ download() {
     fi
 }
 
-if [[ $WP_VERSION =~ [0-9]+\.[0-9]+(\.[0-9]+)? ]]; then
-	WP_TESTS_TAG="tags/$WP_VERSION"
+if [[ $WP_VERSION =~ ^[0-9]+\.[0-9]+$ ]]; then
+	WP_TESTS_TAG="branches/$WP_VERSION"
+elif [[ $WP_VERSION =~ [0-9]+\.[0-9]+\.[0-9]+ ]]; then
+	if [[ $WP_VERSION =~ [0-9]+\.[0-9]+\.[0] ]]; then
+		# version x.x.0 means the first release of the major version, so strip off the .0 and download version x.x
+		WP_TESTS_TAG="tags/${WP_VERSION%??}"
+	else
+		WP_TESTS_TAG="tags/$WP_VERSION"
+	fi
 elif [[ $WP_VERSION == 'nightly' || $WP_VERSION == 'trunk' ]]; then
 	WP_TESTS_TAG="trunk"
 else
@@ -50,18 +59,34 @@ install_wp() {
 	mkdir -p $WP_CORE_DIR
 
 	if [[ $WP_VERSION == 'nightly' || $WP_VERSION == 'trunk' ]]; then
-		mkdir -p /tmp/wordpress-nightly
-		download https://wordpress.org/nightly-builds/wordpress-latest.zip  /tmp/wordpress-nightly/wordpress-nightly.zip
-		unzip -q /tmp/wordpress-nightly/wordpress-nightly.zip -d /tmp/wordpress-nightly/
-		mv /tmp/wordpress-nightly/wordpress/* $WP_CORE_DIR
+		mkdir -p $TMPDIR/wordpress-nightly
+		download https://wordpress.org/nightly-builds/wordpress-latest.zip  $TMPDIR/wordpress-nightly/wordpress-nightly.zip
+		unzip -q $TMPDIR/wordpress-nightly/wordpress-nightly.zip -d $TMPDIR/wordpress-nightly/
+		mv $TMPDIR/wordpress-nightly/wordpress/* $WP_CORE_DIR
 	else
 		if [ $WP_VERSION == 'latest' ]; then
 			local ARCHIVE_NAME='latest'
+		elif [[ $WP_VERSION =~ [0-9]+\.[0-9]+ ]]; then
+			# https serves multiple offers, whereas http serves single.
+			download https://api.wordpress.org/core/version-check/1.7/ $TMPDIR/wp-latest.json
+			if [[ $WP_VERSION =~ [0-9]+\.[0-9]+\.[0] ]]; then
+				# version x.x.0 means the first release of the major version, so strip off the .0 and download version x.x
+				LATEST_VERSION=${WP_VERSION%??}
+			else
+				# otherwise, scan the releases and get the most up to date minor version of the major release
+				local VERSION_ESCAPED=`echo $WP_VERSION | sed 's/\./\\\\./g'`
+				LATEST_VERSION=$(grep -o '"version":"'$VERSION_ESCAPED'[^"]*' $TMPDIR/wp-latest.json | sed 's/"version":"//' | head -1)
+			fi
+			if [[ -z "$LATEST_VERSION" ]]; then
+				local ARCHIVE_NAME="wordpress-$WP_VERSION"
+			else
+				local ARCHIVE_NAME="wordpress-$LATEST_VERSION"
+			fi
 		else
 			local ARCHIVE_NAME="wordpress-$WP_VERSION"
 		fi
-		download https://wordpress.org/${ARCHIVE_NAME}.tar.gz  /tmp/wordpress.tar.gz
-		tar --strip-components=1 -zxmf /tmp/wordpress.tar.gz -C $WP_CORE_DIR
+		download https://wordpress.org/${ARCHIVE_NAME}.tar.gz  $TMPDIR/wordpress.tar.gz
+		tar --strip-components=1 -zxmf $TMPDIR/wordpress.tar.gz -C $WP_CORE_DIR
 	fi
 
 	download https://raw.github.com/markoheijnen/wp-mysqli/master/db.php $WP_CORE_DIR/wp-content/db.php
@@ -80,7 +105,7 @@ install_test_suite() {
 		# set up testing suite
 		mkdir -p $WP_TESTS_DIR
 		svn co --quiet https://develop.svn.wordpress.org/${WP_TESTS_TAG}/tests/phpunit/includes/ $WP_TESTS_DIR/includes
-		svn co --quiet https://develop.svn.wordpress.org/${WP_TESTS_TAG}/tests/phpunit/data/images/ $WP_TESTS_DIR/data/images
+		svn co --quiet https://develop.svn.wordpress.org/${WP_TESTS_TAG}/tests/phpunit/data/ $WP_TESTS_DIR/data
 	fi
 
 	if [ ! -f wp-tests-config.php ]; then
@@ -124,4 +149,4 @@ install_db() {
 
 install_wp
 install_test_suite
-install_db
+install_db
\ No newline at end of file
diff --git a/includes/library.php b/includes/library.php
index 991cb85..e315af3 100644
--- a/includes/library.php
+++ b/includes/library.php
@@ -425,9 +425,26 @@ function bu_navigation_get_posts( $args = '' ) {
 		'include_links' => true,
 		'suppress_filter_posts' => false,
 		'suppress_urls' => false,
-		);
+	);
+
 	$r = wp_parse_args( $args, $defaults );
 
+	// Get last changed date for the WP core `posts` cache group.
+	$last_changed = wp_cache_get_last_changed( 'posts' );
+
+	// Create the key to use for storing the results of the following query.
+	$cache_key = 'get_posts:' . md5( wp_json_encode( $r ) );
+
+	// Check if the results of the following query are in cache.
+	$cached_posts = wp_cache_get( $cache_key, 'bu-navigation-persistent' );
+
+	// If a cached value exists and its `last_changed` property matches
+	// the last changed date for the WP core `posts` cache group,
+	// return the cached query results.
+	if ( $cached_posts && $cached_posts['last_changed'] === $last_changed ) {
+		return $cached_posts['query'];
+	}
+
 	// Start building the query
 	$where = $orderby = '';
 
@@ -532,6 +549,14 @@ function bu_navigation_get_posts( $args = '' ) {
 		$posts = $items;
 	}
 
+	// Cache the `last_changed` value and the query results.
+	$cache_value = array(
+		'last_changed' => $last_changed,
+		'query'        => $posts,
+	);
+
+	wp_cache_set( $cache_key, $cache_value, 'bu-navigation-persistent' );
+
 	return $posts;
 
 }