diff --git a/index.php b/index.php
index 8b095a77a7..b775761838 100644
--- a/index.php
+++ b/index.php
@@ -73,7 +73,7 @@
 	case 'testing':
 	case 'production':
 		ini_set('display_errors', 0);
-		error_reporting(E_ALL & ~E_NOTICE & ~E_DEPRECATED & ~E_STRICT & ~E_USER_NOTICE & ~E_USER_DEPRECATED);
+		error_reporting(E_ALL & ~E_NOTICE & ~E_DEPRECATED & ~E_USER_NOTICE & ~E_USER_DEPRECATED);
 	break;
 
 	default:
diff --git a/system/core/Exceptions.php b/system/core/Exceptions.php
index b1bc2dec5a..bd6c682e3f 100644
--- a/system/core/Exceptions.php
+++ b/system/core/Exceptions.php
@@ -72,8 +72,7 @@ class CI_Exceptions {
 		E_COMPILE_WARNING	=>	'Compile Warning',
 		E_USER_ERROR		=>	'User Error',
 		E_USER_WARNING		=>	'User Warning',
-		E_USER_NOTICE		=>	'User Notice',
-		E_STRICT		=>	'Runtime Notice'
+		E_USER_NOTICE		=>	'User Notice'
 	);
 
 	/**
diff --git a/system/libraries/Encryption.php b/system/libraries/Encryption.php
index a1ad870afe..54d1aa99e4 100644
--- a/system/libraries/Encryption.php
+++ b/system/libraries/Encryption.php
@@ -369,7 +369,7 @@ public function create_key($length)
 	 * @param	array	$params	Input parameters
 	 * @return	string
 	 */
-	public function encrypt($data, array $params = NULL)
+	public function encrypt($data, ?array $params = NULL)
 	{
 		if (($params = $this->_get_params($params)) === FALSE)
 		{
@@ -504,7 +504,7 @@ protected function _openssl_encrypt($data, $params)
 	 * @param	array	$params	Input parameters
 	 * @return	string
 	 */
-	public function decrypt($data, array $params = NULL)
+	public function decrypt($data, ?array $params = NULL)
 	{
 		if (($params = $this->_get_params($params)) === FALSE)
 		{
diff --git a/system/libraries/Session/Session.php b/system/libraries/Session/Session.php
index 03f61e8df9..425d07e9ac 100644
--- a/system/libraries/Session/Session.php
+++ b/system/libraries/Session/Session.php
@@ -389,59 +389,20 @@ protected function _configure(&$params)
 	 */
 	protected function _configure_sid_length()
 	{
-		if (PHP_VERSION_ID < 70100)
-		{
-			$hash_function = ini_get('session.hash_function');
-			if (ctype_digit((string) $hash_function))
-			{
-				if ($hash_function !== '1')
-				{
-					ini_set('session.hash_function', 1);
-				}
-
-				$bits = 160;
-			}
-			elseif ( ! in_array($hash_function, hash_algos(), TRUE))
-			{
-				ini_set('session.hash_function', 1);
-				$bits = 160;
-			}
-			elseif (($bits = strlen(hash($hash_function, 'dummy', false)) * 4) < 160)
-			{
-				ini_set('session.hash_function', 1);
-				$bits = 160;
-			}
-
-			$bits_per_character = (int) ini_get('session.hash_bits_per_character');
-			$sid_length         = (int) ceil($bits / $bits_per_character);
-		}
-		else
-		{
-			$bits_per_character = (int) ini_get('session.sid_bits_per_character');
-			$sid_length         = (int) ini_get('session.sid_length');
-			if (($bits = $sid_length * $bits_per_character) < 160)
-			{
-				// Add as many more characters as necessary to reach at least 160 bits
-				$sid_length += (int) ceil((160 % $bits) / $bits_per_character);
-				ini_set('session.sid_length', $sid_length);
-			}
-		}
-
-		// Yes, 4,5,6 are the only known possible values as of 2016-10-27
-		switch ($bits_per_character)
-		{
-			case 4:
-				$this->_sid_regexp = '[0-9a-f]';
-				break;
-			case 5:
-				$this->_sid_regexp = '[0-9a-v]';
-				break;
-			case 6:
-				$this->_sid_regexp = '[0-9a-zA-Z,-]';
-				break;
-		}
-
-		$this->_sid_regexp .= '{'.$sid_length.'}';
+        $bits_per_character = (int) ini_get('session.sid_bits_per_character');
+        $sid_length         = (int) ini_get('session.sid_length');
+
+        // We force the PHP defaults.
+        if (PHP_VERSION_ID < 90000) {
+            if ($bits_per_character !== 4) {
+                ini_set('session.sid_bits_per_character', '4');
+            }
+            if ($sid_length !== 32) {
+                ini_set('session.sid_length', '32');
+            }
+        }
+
+        $this->_sid_regexp = '[0-9a-f]{32}';
 	}
 
 	// ------------------------------------------------------------------------
diff --git a/tests/Bootstrap.php b/tests/Bootstrap.php
index ada6a5998b..10a21f3255 100644
--- a/tests/Bootstrap.php
+++ b/tests/Bootstrap.php
@@ -1,7 +1,7 @@
 <?php
 // Errors on full!
 ini_set('display_errors', 1);
-error_reporting(E_ALL | E_STRICT);
+error_reporting(E_ALL);
 
 $dir = realpath(dirname(__FILE__));