diff --git a/.travis.yml b/.travis.yml
index a6bcdd089..b73a1491f 100644
--- a/.travis.yml
+++ b/.travis.yml
@@ -1,9 +1,11 @@
 language: php
 
-php:
-  - 7.0
-  - 7.1
-  - 7.2
+matrix:
+  include:
+    - php: 7.2
+    - php: nightly
+  allow_failures:
+    - php: nightly
 
 install: travis_retry composer install --no-interaction --prefer-source
 
diff --git a/composer.json b/composer.json
index c4e431216..f9b2defa3 100644
--- a/composer.json
+++ b/composer.json
@@ -1,6 +1,6 @@
 {
 	"name": "chillerlan/php-qrcode",
-	"description": "A QR code generator. PHP 7+",
+	"description": "A QR code generator. PHP 7.2+",
 	"homepage": "https://github.com/chillerlan/php-qrcode",
 	"license": "MIT",
 	"minimum-stability": "stable",
@@ -20,15 +20,13 @@
 		}
 	],
 	"require": {
-		"php": ">=7.0.3",
-		"chillerlan/php-traits": "^1.1"
+		"php": ">=7.2.0",
+		"chillerlan/php-traits": "^2.0"
 	},
 	"require-dev": {
-		"phpunit/phpunit": "^6.5",
+		"phpunit/phpunit": "^7.3",
 		"chillerlan/php-authenticator": "^2.0"
 	},
-	"suggest": {
-	},
 	"autoload": {
 		"psr-4": {
 			"chillerlan\\QRCode\\": "src/"
diff --git a/phpunit.xml b/phpunit.xml
index 25e82cf68..2a41c5d15 100644
--- a/phpunit.xml
+++ b/phpunit.xml
@@ -8,7 +8,6 @@
          convertWarningsToExceptions="true"
          processIsolation="false"
          stopOnFailure="false"
-         syntaxCheck="false"
         >
     <filter>
         <whitelist processUncoveredFilesFromWhitelist="true">
diff --git a/src/Data/QRDataAbstract.php b/src/Data/QRDataAbstract.php
index 3ec3a2a9e..645f53d45 100644
--- a/src/Data/QRDataAbstract.php
+++ b/src/Data/QRDataAbstract.php
@@ -18,8 +18,9 @@ use chillerlan\QRCode\{
 use chillerlan\QRCode\Helpers\{
 	BitBuffer, Polynomial
 };
-use chillerlan\Traits\ClassLoader;
-use chillerlan\Traits\ContainerInterface;
+use chillerlan\Traits\{
+	ClassLoader, ImmutableSettingsInterface
+};
 
 /**
  * Processes the binary data and maps it on a matrix which is then being returned
@@ -89,10 +90,10 @@ abstract class QRDataAbstract implements QRDataInterface{
 	/**
 	 * QRDataInterface constructor.
 	 *
-	 * @param \chillerlan\Traits\ContainerInterface $options
+	 * @param \chillerlan\Traits\ImmutableSettingsInterface $options
 	 * @param string|null                           $data
 	 */
-	public function __construct(ContainerInterface $options, string $data = null){
+	public function __construct(ImmutableSettingsInterface $options, string $data = null){
 		$this->options = $options;
 
 		if($data !== null){
@@ -186,6 +187,7 @@ abstract class QRDataAbstract implements QRDataInterface{
 	 * @throws \chillerlan\QRCode\Data\QRCodeDataException
 	 */
 	protected function getMinimumVersion():int{
+		$maxlength = 0;
 
 		// guess the version number within the given range
 		foreach(range(max(1, $this->options->versionMin), min($this->options->versionMax, 40)) as $version){
diff --git a/src/Output/QROutputAbstract.php b/src/Output/QROutputAbstract.php
index 823450014..77904fcfe 100644
--- a/src/Output/QROutputAbstract.php
+++ b/src/Output/QROutputAbstract.php
@@ -15,7 +15,7 @@ namespace chillerlan\QRCode\Output;
 use chillerlan\QRCode\{
 	Data\QRMatrix, QRCode
 };
-use chillerlan\Traits\ContainerInterface;
+use chillerlan\Traits\ImmutableSettingsInterface;
 
 /**
  *
@@ -50,10 +50,10 @@ abstract class QROutputAbstract implements QROutputInterface{
 	/**
 	 * QROutputAbstract constructor.
 	 *
-	 * @param \chillerlan\Traits\ContainerInterface $options
+	 * @param \chillerlan\Traits\ImmutableSettingsInterface $options
 	 * @param \chillerlan\QRCode\Data\QRMatrix      $matrix
 	 */
-	public function __construct(ContainerInterface $options, QRMatrix $matrix){
+	public function __construct(ImmutableSettingsInterface $options, QRMatrix $matrix){
 		$this->options     = $options;
 		$this->matrix      = $matrix;
 		$this->moduleCount = $this->matrix->size();
diff --git a/src/QRCode.php b/src/QRCode.php
index a2d9cd0aa..13ba93ae6 100755
--- a/src/QRCode.php
+++ b/src/QRCode.php
@@ -19,7 +19,7 @@ use chillerlan\QRCode\Output\{
 	QRCodeOutputException, QRImage, QRMarkup, QROutputInterface, QRString
 };
 use chillerlan\Traits\{
-	ClassLoader, ContainerInterface
+	ClassLoader, ImmutableSettingsInterface
 };
 
 /**
@@ -106,9 +106,9 @@ class QRCode{
 	/**
 	 * QRCode constructor.
 	 *
-	 * @param \chillerlan\Traits\ContainerInterface|null $options
+	 * @param \chillerlan\Traits\ImmutableSettingsInterface|null $options
 	 */
-	public function __construct(ContainerInterface $options = null){
+	public function __construct(ImmutableSettingsInterface $options = null){
 		mb_internal_encoding('UTF-8');
 
 		$this->setOptions($options ?? new QROptions);
@@ -117,12 +117,12 @@ class QRCode{
 	/**
 	 * Sets the options, called internally by the constructor
 	 *
-	 * @param \chillerlan\Traits\ContainerInterface $options
+	 * @param \chillerlan\Traits\ImmutableSettingsInterface $options
 	 *
 	 * @return \chillerlan\QRCode\QRCode
 	 * @throws \chillerlan\QRCode\QRCodeException
 	 */
-	public function setOptions(ContainerInterface $options):QRCode{
+	public function setOptions(ImmutableSettingsInterface $options):QRCode{
 
 		if(!array_key_exists($options->eccLevel, $this::ECC_MODES)){
 			throw new QRCodeException('Invalid error correct level: '.$options->eccLevel);
diff --git a/src/QROptions.php b/src/QROptions.php
index 5468e98f3..a33cc1d4a 100644
--- a/src/QROptions.php
+++ b/src/QROptions.php
@@ -12,7 +12,7 @@
 
 namespace chillerlan\QRCode;
 
-use chillerlan\Traits\ContainerAbstract;
+use chillerlan\Traits\ImmutableSettingsAbstract;
 
 /**
  * @property int    $version
@@ -45,6 +45,6 @@ use chillerlan\Traits\ContainerAbstract;
  *
  * @property array  $moduleValues
  */
-class QROptions extends ContainerAbstract{
+class QROptions extends ImmutableSettingsAbstract{
 	use QROptionsTrait;
 }