diff --git a/.gitignore b/.gitignore
new file mode 100644
index 0000000..d8a7996
--- /dev/null
+++ b/.gitignore
@@ -0,0 +1,2 @@
+composer.lock
+vendor/
diff --git a/.travis.yml b/.travis.yml
index 193d0c3..9fa3cad 100644
--- a/.travis.yml
+++ b/.travis.yml
@@ -1,18 +1,10 @@
-language: php
-php:
-    - 7.1
-    - 7.2
-    - 7.3
-    - 7.4
+language: minimal
+env:
+    - PHP_VERSION=7.4-dev
+    - PHP_VERSION=8.0-dev
 
 script:
-    - vendor/bin/phpstan analyse -l 5 src
+    - docker run --rm -it -v "$PWD":/var/www/html peckadesign/php:${PHP_VERSION} vendor/bin/phpstan analyse -l 7 src/
 
 before_script:
-    - travis_retry composer install --no-interaction --prefer-dist
-
-sudo: false
-
-cache:
-    directories:
-        - $HOME/.composer/cache
+    - docker run --rm -it -v "$PWD":/var/www/html peckadesign/php:${PHP_VERSION} composer install --no-interaction --prefer-dist
diff --git a/composer.json b/composer.json
index 97f6703..93c1f91 100644
--- a/composer.json
+++ b/composer.json
@@ -16,10 +16,11 @@
 		}
 	],
 	"require": {
-		"tracy/tracy": "~2.4.18"
+		"php": "7.4.* || 8.0.*",
+		"tracy/tracy": ">= 2.4.18"
 	},
 	"require-dev": {
-		"phpstan/phpstan": "0.12.11"
+		"phpstan/phpstan": "0.12.*"
 	},
 	"autoload": {
 		"psr-0": {
diff --git a/src/Pd/Diagnostics/DatabaseInfoPanel.php b/src/Pd/Diagnostics/DatabaseInfoPanel.php
index 34bdf82..053466a 100644
--- a/src/Pd/Diagnostics/DatabaseInfoPanel.php
+++ b/src/Pd/Diagnostics/DatabaseInfoPanel.php
@@ -10,21 +10,20 @@
  */
 class DatabaseInfoPanel implements Tracy\IBarPanel
 {
-	/** @var string[] $databaseParams [{key => val}] */
-	private $databaseParams;
+	/** @var array<string, string> */
+	private array $databaseParams;
 
-	/** @var string[] */
-	private $possibleDbNameKeys = array('dbname', 'database');
+	/** @var array<string> */
+	private array $possibleDbNameKeys = ['dbname', 'database'];
 
-	/** @var IDatabaseInfoPanelStyleHandler|NULL */
-	private $styleCallback;
+	private ?IDatabaseInfoPanelStyleHandler$styleCallback;
 
 	/**
-	 * @param string[] $databaseParams All database parameters in [{key => val}] format
-	 * @param string|NULL $customDbNameKey Custom key of DB name value
-	 * @param IDatabaseInfoPanelStyleHandler $styleCallback Handler with formating of DB name label in panel
+	 * @param array<string, string> $databaseParams All database parameters in [{key => val}] format
+	 * @param string|null $customDbNameKey Custom key of DB name value
+	 * @param IDatabaseInfoPanelStyleHandler|null $styleCallback Handler with formating of DB name label in panel
 	 */
-	public function __construct(array $databaseParams, $customDbNameKey = NULL, IDatabaseInfoPanelStyleHandler $styleCallback = NULL)
+	public function __construct(array $databaseParams, ?string $customDbNameKey = NULL, ?IDatabaseInfoPanelStyleHandler $styleCallback = NULL)
 	{
 		$this->setDatabaseParams($databaseParams);
 
@@ -34,14 +33,17 @@ public function __construct(array $databaseParams, $customDbNameKey = NULL, IDat
 	}
 
 
-	private function setDatabaseParams(array $databaseParams)
+	/**
+	 * @param array<string, string> $databaseParams
+	 */
+	private function setDatabaseParams(array $databaseParams): void
 	{
 		if (array_key_exists('password', $databaseParams)) unset($databaseParams['password']);
 		$this->databaseParams = $databaseParams;
 	}
 
 
-	private function getDatabaseName()
+	private function getDatabaseName(): string
 	{
 		foreach ($this->possibleDbNameKeys as $key) {
 			if (array_key_exists($key, $this->databaseParams)) return $this->databaseParams[$key];
@@ -50,7 +52,7 @@ private function getDatabaseName()
 	}
 
 
-	public function getTab()
+	public function getTab(): string
 	{
 		if ($this->styleCallback) $style = ' style="' . $this->styleCallback->getStyle($this->getDatabaseName(), $this->databaseParams) . '"';
 		else $style = '';
@@ -62,10 +64,11 @@ public function getTab()
 	}
 
 
-	public function getPanel()
+	public function getPanel(): string
 	{
 		ob_start();
 		include __DIR__ . '/DatabaseInfoPanel.phtml';
-		return ob_get_clean();
+		return (string) ob_get_clean();
 	}
+
 }
diff --git a/src/Pd/Diagnostics/IDatabaseInfoPanelStyleHandler.php b/src/Pd/Diagnostics/IDatabaseInfoPanelStyleHandler.php
index 23f7cb0..ff8f56f 100644
--- a/src/Pd/Diagnostics/IDatabaseInfoPanelStyleHandler.php
+++ b/src/Pd/Diagnostics/IDatabaseInfoPanelStyleHandler.php
@@ -10,9 +10,9 @@
 interface IDatabaseInfoPanelStyleHandler
 {
 	/**
-	 * @var string $databaseName Database name
-	 * @var string[] $databaseParams All database parameters
+	 * @param string $databaseName Database name
+	 * @param array<string, string> $databaseParams All database parameters
 	 * @return string Content of DB name label style atribut
 	 */
-	public function getStyle($databaseName, $databaseParams);
+	public function getStyle(string $databaseName, array $databaseParams): string;
 }