diff --git a/.github/workflows/main.yml b/.github/workflows/main.yml
index b623970..e067caa 100644
--- a/.github/workflows/main.yml
+++ b/.github/workflows/main.yml
@@ -14,7 +14,7 @@ jobs:
     
     strategy:
       matrix:
-        php: ['5.6', '7.3', '7.4', '8.0', '8.1']
+        php: ['7.1', '7.3', '7.4', '8.0', '8.1']
 
     runs-on: ubuntu-latest
 
diff --git a/Mf2/Parser.php b/Mf2/Parser.php
index c7cc02d..5670b61 100644
--- a/Mf2/Parser.php
+++ b/Mf2/Parser.php
@@ -1383,7 +1383,7 @@ public function upgradeRelTagToCategory(DOMElement $el) {
 	 * @param DOMElement $context optionally specify an element from which to parse microformats
 	 * @return array An array containing all the microformats found in the current document
 	 */
-	public function parse($convertClassic = true, DOMElement $context = null) {
+	public function parse($convertClassic = true, ?DOMElement $context = null) {
 		$this->convertClassic = $convertClassic;
 		$mfs = $this->parse_recursive($context);
 
@@ -1411,7 +1411,7 @@ public function parse($convertClassic = true, DOMElement $context = null) {
 	 * @param int $depth: recursion depth
 	 * @return array
 	 */
-	public function parse_recursive(DOMElement $context = null, $depth = 0) {
+	public function parse_recursive(?DOMElement $context = null, $depth = 0) {
 		$mfs = array();
 		$mfElements = $this->getRootMF($context);
 
@@ -1516,7 +1516,7 @@ public function parseFromId($id, $convertClassic=true) {
 	 * @param DOMElement $context
 	 * @return DOMNodeList
 	 */
-	public function getRootMF(DOMElement $context = null) {
+	public function getRootMF(?DOMElement $context = null) {
 		// start with mf2 root class name xpath
 		$xpaths = array(
 			'(php:function("\\Mf2\\classHasMf2RootClassname", normalize-space(@class)))'
diff --git a/composer.json b/composer.json
index bdd43d7..d08080b 100644
--- a/composer.json
+++ b/composer.json
@@ -11,7 +11,7 @@
     ],
     "bin": ["bin/fetch-mf2", "bin/parse-mf2"],
     "require": {
-        "php": ">=5.6.0"
+        "php": ">=7.1.0"
     },
     "config": {
         "platform": {
diff --git a/phpcs.xml b/phpcs.xml
index 8e94cdd..7597fef 100644
--- a/phpcs.xml
+++ b/phpcs.xml
@@ -3,5 +3,5 @@
 	<description>PHP-MF2 Standards</description>
 	<file>./Mf2/Parser.php</file>
 	<rule ref="PHPCompatibility"/>
-	<config name="testVersion" value="5.6-"/>
+	<config name="testVersion" value="7.1-"/>
 </ruleset>