diff --git a/composer.json b/composer.json
index aff3b8590..23617dbf8 100644
--- a/composer.json
+++ b/composer.json
@@ -18,7 +18,7 @@
 		"source": "https://github.com/cakephp/cakephp"
 	},
 	"require": {
-		"php": "^7.0 || ^8.0"
+		"php": "^8.0"
 	},
 	"suggest": {
 		"ext-openssl": "You need to install ext-openssl or ext-mcrypt to use AES-256 encryption",
diff --git a/lib/Cake/Model/ModelValidator.php b/lib/Cake/Model/ModelValidator.php
index 406c0816c..7c34d94e4 100644
--- a/lib/Cake/Model/ModelValidator.php
+++ b/lib/Cake/Model/ModelValidator.php
@@ -461,10 +461,10 @@ class ModelValidator implements ArrayAccess, IteratorAggregate, Countable {
 /**
  * Returns whether a rule set is defined for a field or not
  *
- * @param string $field name of the field to check
+ * @param mixed $field name of the field to check
  * @return bool
  */
-	public function offsetExists($field) {
+	public function offsetExists(mixed $field) : bool {
 		$this->_parseRules();
 		return isset($this->_fields[$field]);
 	}
@@ -472,10 +472,10 @@ class ModelValidator implements ArrayAccess, IteratorAggregate, Countable {
 /**
  * Returns the rule set for a field
  *
- * @param string $field name of the field to check
+ * @param mixed $field name of the field to check
  * @return CakeValidationSet
  */
-	public function offsetGet($field) {
+	public function offsetGet(mixed $field) : mixed {
 		$this->_parseRules();
 		return $this->_fields[$field];
 	}
@@ -487,7 +487,7 @@ class ModelValidator implements ArrayAccess, IteratorAggregate, Countable {
  * @param array|CakeValidationSet $rules set of rules to apply to field
  * @return void
  */
-	public function offsetSet($field, $rules) {
+	public function offsetSet(mixed $field, mixed $rules) : void {
 		$this->_parseRules();
 		if (!$rules instanceof CakeValidationSet) {
 			$rules = new CakeValidationSet($field, $rules);
@@ -503,7 +503,7 @@ class ModelValidator implements ArrayAccess, IteratorAggregate, Countable {
  * @param string $field name of the field to unset
  * @return void
  */
-	public function offsetUnset($field) {
+	public function offsetUnset(mixed $field) : void {
 		$this->_parseRules();
 		unset($this->_fields[$field]);
 	}
diff --git a/lib/Cake/Model/Validator/CakeValidationSet.php b/lib/Cake/Model/Validator/CakeValidationSet.php
index eab540861..e04453e05 100644
--- a/lib/Cake/Model/Validator/CakeValidationSet.php
+++ b/lib/Cake/Model/Validator/CakeValidationSet.php
@@ -307,20 +307,20 @@ class CakeValidationSet implements ArrayAccess, IteratorAggregate, Countable {
 /**
  * Returns whether an index exists in the rule set
  *
- * @param string $index name of the rule
+ * @param mixed $index name of the rule
  * @return bool
  */
-	public function offsetExists($index) {
+	public function offsetExists(mixed $index) : bool {
 		return isset($this->_rules[$index]);
 	}
 
 /**
  * Returns a rule object by its index
  *
- * @param string $index name of the rule
+ * @param mixed $index name of the rule
  * @return CakeValidationRule
  */
-	public function offsetGet($index) {
+	public function offsetGet(mixed $index) : mixed {
 		return $this->_rules[$index];
 	}
 
@@ -335,7 +335,7 @@ class CakeValidationSet implements ArrayAccess, IteratorAggregate, Countable {
  * @return void
  * @see http://www.php.net/manual/en/arrayobject.offsetset.php
  */
-	public function offsetSet($index, $rule) {
+	public function offsetSet(mixed $index, mixed $rule) : void {
 		$this->setRule($index, $rule);
 	}
 
@@ -345,7 +345,7 @@ class CakeValidationSet implements ArrayAccess, IteratorAggregate, Countable {
  * @param string $index name of the rule
  * @return void
  */
-	public function offsetUnset($index) {
+	public function offsetUnset(mixed $index) : void {
 		unset($this->_rules[$index]);
 	}
 
diff --git a/lib/Cake/Network/CakeRequest.php b/lib/Cake/Network/CakeRequest.php
index adc0b99b6..5d4bd7ee0 100644
--- a/lib/Cake/Network/CakeRequest.php
+++ b/lib/Cake/Network/CakeRequest.php
@@ -1113,10 +1113,10 @@ class CakeRequest implements ArrayAccess {
 /**
  * Array access read implementation
  *
- * @param string $name Name of the key being accessed.
+ * @param mixed $name Name of the key being accessed.
  * @return mixed
  */
-	public function offsetGet($name) {
+	public function offsetGet(mixed $name) : mixed {
 		if (isset($this->params[$name])) {
 			return $this->params[$name];
 		}
@@ -1132,21 +1132,21 @@ class CakeRequest implements ArrayAccess {
 /**
  * Array access write implementation
  *
- * @param string $name Name of the key being written
+ * @param mixed $name Name of the key being written
  * @param mixed $value The value being written.
  * @return void
  */
-	public function offsetSet($name, $value) {
+	public function offsetSet(mixed $name, mixed $value) : void {
 		$this->params[$name] = $value;
 	}
 
 /**
  * Array access isset() implementation
  *
- * @param string $name thing to check.
+ * @param mixed $name thing to check.
  * @return bool
  */
-	public function offsetExists($name) {
+	public function offsetExists(mixed $name) : bool {
 		if ($name === 'url' || $name === 'data') {
 			return true;
 		}
@@ -1159,7 +1159,7 @@ class CakeRequest implements ArrayAccess {
  * @param string $name Name to unset.
  * @return void
  */
-	public function offsetUnset($name) {
+	public function offsetUnset(mixed $name) : void {
 		unset($this->params[$name]);
 	}
 
diff --git a/lib/Cake/Network/Http/HttpSocketResponse.php b/lib/Cake/Network/Http/HttpSocketResponse.php
index 69c6da725..5b3f7dc53 100644
--- a/lib/Cake/Network/Http/HttpSocketResponse.php
+++ b/lib/Cake/Network/Http/HttpSocketResponse.php
@@ -386,20 +386,20 @@ class HttpSocketResponse implements ArrayAccess {
 /**
  * ArrayAccess - Offset Exists
  *
- * @param string $offset Offset to check.
+ * @param mixed $offset Offset to check.
  * @return bool
  */
-	public function offsetExists($offset) {
+	public function offsetExists(mixed $offset) : bool {
 		return in_array($offset, array('raw', 'status', 'header', 'body', 'cookies'));
 	}
 
 /**
  * ArrayAccess - Offset Get
  *
- * @param string $offset Offset to get.
+ * @param mixed $offset Offset to get.
  * @return mixed
  */
-	public function offsetGet($offset) {
+	public function offsetGet(mixed $offset) : mixed {
 		switch ($offset) {
 			case 'raw':
 				$firstLineLength = strpos($this->raw, "\r\n") + 2;
@@ -433,11 +433,11 @@ class HttpSocketResponse implements ArrayAccess {
 /**
  * ArrayAccess - Offset Set
  *
- * @param string $offset Offset to set.
+ * @param mixed $offset Offset to set.
  * @param mixed $value Value.
  * @return void
  */
-	public function offsetSet($offset, $value) {
+	public function offsetSet(mixed $offset, mixed $value) : void {
 	}
 
 /**
@@ -446,7 +446,7 @@ class HttpSocketResponse implements ArrayAccess {
  * @param string $offset Offset to unset.
  * @return void
  */
-	public function offsetUnset($offset) {
+	public function offsetUnset(mixed $offset) : void {
 	}
 
 /**
@@ -454,7 +454,7 @@ class HttpSocketResponse implements ArrayAccess {
  *
  * @return string
  */
-	public function __toString() {
+	public function __tostring() {
 		return $this->body();
 	}