diff --git a/composer.json b/composer.json
index 4b0f577..027160e 100644
--- a/composer.json
+++ b/composer.json
@@ -12,14 +12,14 @@
     "require": {
         "php": ">=7.4",
         "ext-json": "*",
-        "psr/http-message": "^1.0",
+        "psr/http-message": "^1.1 || ^2.0",
         "shrikeh/teapot": "^2.3.1",
         "theodorejb/peachy-sql": "^6.1"
     },
     "require-dev": {
         "phpunit/phpunit": "^9.6",
-        "psalm/plugin-phpunit": "^0.18.4",
-        "vimeo/psalm": "^5.15"
+        "psalm/plugin-phpunit": "^0.19",
+        "vimeo/psalm": "^5.26"
     },
     "autoload": {
         "psr-4": {"theodorejb\\Phaster\\": "src/"}
diff --git a/src/Helpers.php b/src/Helpers.php
index 51fb83c..7bcce89 100644
--- a/src/Helpers.php
+++ b/src/Helpers.php
@@ -84,14 +84,14 @@ public static function mapRows(\Generator $rows, array $fieldProps): array
             $nullParents = [];
 
             foreach ($aliasMap as $colName => $prop) {
-                if ($prop->getValue) {
+                if ($prop->getValue !== null) {
                     /** @var mixed $value */
                     $value = ($prop->getValue)($row);
                 } else {
                     /** @var mixed $value */
                     $value = $row[$colName];
 
-                    if ($prop->type) {
+                    if ($prop->type !== null) {
                         settype($value, $prop->type);
                     } elseif (is_string($value) && $prop->timeZone !== false) {
                         $value = (new \DateTimeImmutable($value, $prop->timeZone))->format(\DateTime::ATOM);
diff --git a/test/src/DbConnector.php b/test/src/DbConnector.php
index fb105ca..009de12 100644
--- a/test/src/DbConnector.php
+++ b/test/src/DbConnector.php
@@ -41,8 +41,8 @@ public static function getMysqlConn(): mysqli
 
             self::$mysqlConn = new mysqli($c->getMysqlHost(), $c->getMysqlUser(), $c->getMysqlPassword(), $c->getMysqlDatabase(), $dbPort);
 
-            if (self::$mysqlConn->connect_error) {
-                throw new Exception('Failed to connect to MySQL: (' . self::$mysqlConn->connect_errno . ') ' . self::$mysqlConn->connect_error);
+            if (self::$mysqlConn->connect_error !== null) {
+                throw new Exception('Failed to connect to MySQL: ' . self::$mysqlConn->connect_error);
             }
 
             self::createMysqlTestTable(self::$mysqlConn);