diff --git a/composer.json b/composer.json
index 199fd9f7..7a01a5e8 100644
--- a/composer.json
+++ b/composer.json
@@ -165,6 +165,9 @@
             "mpdf/psr-log-aware-trait": [
                 "patches/mpdf-psr-log-aware-trait-void-return.patch",
                 "patches/mpdf-mpdf-psr-log-aware-trait-void-return.patch"
+            ],
+            "mpdf/psr-http-message-shim": [
+                "patches/mpdf-psr-http-message-shim-php8-compat.patch"
             ]
         },
         "installer-paths": {
diff --git a/inc/admin-pages/class-email-list-admin-page.php b/inc/admin-pages/class-email-list-admin-page.php
index 38b219cc..b21aa45c 100644
--- a/inc/admin-pages/class-email-list-admin-page.php
+++ b/inc/admin-pages/class-email-list-admin-page.php
@@ -242,13 +242,13 @@ public function handle_send_new_test_modal() {
 		}
 
 		$from = [
-			'name'  => wu_get_setting('from_name'),
-			'email' => wu_get_setting('from_email'),
+			'name'  => wu_get_setting('from_name', ''),
+			'email' => wu_get_setting('from_email', ''),
 		];
 
 		$to = [
 			[
-				'name'  => wu_get_setting('from_name'),
+				'name'  => wu_get_setting('from_name', ''),
 				'email' => $send_to,
 			],
 		];
diff --git a/inc/admin-pages/class-top-admin-nav-menu.php b/inc/admin-pages/class-top-admin-nav-menu.php
index bbe0de41..5524a90a 100644
--- a/inc/admin-pages/class-top-admin-nav-menu.php
+++ b/inc/admin-pages/class-top-admin-nav-menu.php
@@ -191,10 +191,11 @@ public function add_top_bar_menus($wp_admin_bar): void {
 		}
 
 		/*
-		 * Add the settings sub-menus.
+		 * Add the settings sub-menus using the lightweight section names
+		 * to avoid triggering the full default_sections() field registration.
 		 */
 		if (current_user_can('wu_read_settings')) {
-			$settings_tabs = Settings::get_instance()->get_sections();
+			$settings_tabs = Settings::get_instance()->get_section_names();
 
 			$addon_tabs = [];
 
diff --git a/inc/checkout/class-checkout.php b/inc/checkout/class-checkout.php
index adbede11..b2c8f238 100644
--- a/inc/checkout/class-checkout.php
+++ b/inc/checkout/class-checkout.php
@@ -942,7 +942,7 @@ public function process_order() {
 				$this->membership->set_date_trial_end(gmdate('Y-m-d 23:59:59', $this->order->get_billing_start_date()));
 				$this->membership->set_date_expiration(gmdate('Y-m-d 23:59:59', $this->order->get_billing_start_date()));
 
-				if (wu_get_setting('allow_trial_without_payment_method') && $this->customer->get_email_verification() !== 'pending') {
+				if (wu_get_setting('allow_trial_without_payment_method', false) && $this->customer->get_email_verification() !== 'pending') {
 					/*
 					 * In this particular case, we need to set the status to trialing here as we will not update the membership after and then, publish the site.
 					 */
diff --git a/inc/checkout/class-legacy-checkout.php b/inc/checkout/class-legacy-checkout.php
index 992b6381..98725870 100644
--- a/inc/checkout/class-legacy-checkout.php
+++ b/inc/checkout/class-legacy-checkout.php
@@ -321,7 +321,7 @@ public function check_geolocation(): void {
 
 		$this->session->set('geolocation', $location);
 
-		$allowed_countries = wu_get_setting('allowed_countries');
+		$allowed_countries = wu_get_setting('allowed_countries', []);
 
 		if (isset($location['country']) && $location['country'] && $allowed_countries) {
 			if ( ! in_array($location['country'], $allowed_countries, true)) {
@@ -754,7 +754,7 @@ public function sort_steps_and_fields($a, $b) {
 	public function form_fields($current_plan = false, $step = 'plan', $freq = false): void {
 
 		/** Select the default frequency */
-		$freq = $freq ?: wu_get_setting('default_pricing_option');
+		$freq = $freq ?: wu_get_setting('default_pricing_option', 1);
 
 		?>
 
diff --git a/inc/checkout/signup-fields/class-signup-field-payment.php b/inc/checkout/signup-fields/class-signup-field-payment.php
index ad0b35dc..b1b87787 100644
--- a/inc/checkout/signup-fields/class-signup-field-payment.php
+++ b/inc/checkout/signup-fields/class-signup-field-payment.php
@@ -184,7 +184,7 @@ public function to_fields_array($attributes) {
 		 * Checks if we need to add the
 		 * auto renew field.
 		 */
-		if ( ! wu_get_setting('force_auto_renew', 1)) {
+		if ( ! wu_get_setting('force_auto_renew', true)) {
 			$auto_renewable_gateways = Gateway_Manager::get_instance()->get_auto_renewable_gateways();
 
 			$fields['auto_renew'] = [
diff --git a/inc/checkout/signup-fields/class-signup-field-template-selection.php b/inc/checkout/signup-fields/class-signup-field-template-selection.php
index 8ce1d9a9..47a7c5bb 100644
--- a/inc/checkout/signup-fields/class-signup-field-template-selection.php
+++ b/inc/checkout/signup-fields/class-signup-field-template-selection.php
@@ -328,7 +328,7 @@ public function to_fields_array($attributes) {
 
 		$customer_sites = [];
 
-		if (wu_get_setting('allow_own_site_as_template')) {
+		if (wu_get_setting('allow_own_site_as_template', false)) {
 			$customer = wu_get_current_customer();
 
 			if ($customer) {
diff --git a/inc/class-dashboard-widgets.php b/inc/class-dashboard-widgets.php
index a4e9d80d..dd14447a 100644
--- a/inc/class-dashboard-widgets.php
+++ b/inc/class-dashboard-widgets.php
@@ -157,14 +157,14 @@ public function register_widgets(): void {
 		/*
 		 * Maintenance Mode Widget
 		 */
-		if (wu_get_setting('maintenance_mode')) {
+		if (wu_get_setting('maintenance_mode', false)) {
 			\WP_Ultimo\UI\Site_Maintenance_Element::get_instance()->as_metabox($screen->id, 'side');
 		}
 
 		/*
 		 * Domain Mapping Widget
 		 */
-		if (wu_get_setting('enable_domain_mapping') && wu_get_setting('custom_domains')) {
+		if (wu_get_setting('enable_domain_mapping', false) && wu_get_setting('custom_domains', false)) {
 			\WP_Ultimo\UI\Domain_Mapping_Element::get_instance()->as_metabox($screen->id, 'side');
 		}
 	}
diff --git a/inc/class-maintenance-mode.php b/inc/class-maintenance-mode.php
index defa048d..1c70c437 100644
--- a/inc/class-maintenance-mode.php
+++ b/inc/class-maintenance-mode.php
@@ -32,7 +32,7 @@ public function init(): void {
 
 		add_action('init', [$this, 'add_settings']);
 
-		if (wu_get_setting('maintenance_mode')) {
+		if (wu_get_setting('maintenance_mode', false)) {
 			$this->hooks();
 		}
 	}
diff --git a/inc/class-settings.php b/inc/class-settings.php
index aa5de165..1abfe424 100644
--- a/inc/class-settings.php
+++ b/inc/class-settings.php
@@ -204,7 +204,14 @@ public function get_setting($setting, $default_value = false) {
 			_doing_it_wrong(esc_html($setting), esc_html__('Dashes are no longer supported when registering a setting. You should change it to underscores in later versions.', 'ultimate-multisite'), '2.0.0');
 		}
 
-		$setting_value = $settings[ $setting ] ?? $default_value;
+		if (isset($settings[ $setting ])) {
+			$setting_value = $settings[ $setting ];
+		} elseif (false !== $default_value) {
+			$setting_value = $default_value;
+		} else {
+			$defaults      = static::get_setting_defaults();
+			$setting_value = $defaults[ $setting ] ?? false;
+		}
 
 		return apply_filters('wu_get_setting', $setting_value, $setting, $default_value, $settings);
 	}
@@ -518,15 +525,6 @@ function ($fields) use ($field_slug, $atts) {
 			},
 			$priority
 		);
-
-		$settings = $this->get_all();
-
-		/*
-		 * Makes sure we install the default value if it is not set yet.
-		 */
-		if (isset($atts['default']) && null !== $atts['default'] && ! isset($settings[ $field_slug ])) {
-			$this->save_setting($field_slug, $atts['default']);
-		}
 	}
 
 	/**
@@ -1832,6 +1830,200 @@ public function default_sections(): void {
 		do_action('wu_settings_other');
 	}
 
+	/**
+	 * Returns a flat map of setting keys to their default values.
+	 *
+	 * This is used as a lightweight fallback in get_setting() so that
+	 * default_sections() (which is expensive) does not need to run on
+	 * every page load.
+	 *
+	 * @since 2.5.0
+	 * @return array<string, mixed>
+	 */
+	public static function get_setting_defaults(): array {
+
+		return [
+			// General
+			'company_name'                       => '',
+			'company_logo'                       => '',
+			'company_email'                      => '',
+			'company_address'                    => '',
+			'company_country'                    => 'US',
+			'currency_symbol'                    => 'USD',
+			'currency_position'                  => '%s %v',
+			'decimal_separator'                  => '.',
+			'thousand_separator'                 => ',',
+			'precision'                          => '2',
+			'enable_error_reporting'             => 0,
+			'enable_beta_updates'                => 0,
+
+			// Login & Registration
+			'enable_registration'                => 1,
+			'enable_email_verification'          => 'free_only',
+			'enable_custom_login_page'           => 0,
+			'default_login_page'                 => 0,
+			'obfuscate_original_login_url'       => 0,
+			'subsite_custom_login_logo'          => 0,
+			'force_publish_sites_sync'           => 0,
+			'minimum_password_strength'          => 'medium',
+			'default_role'                       => 'administrator',
+			'add_users_to_main_site'             => 0,
+			'main_site_default_role'             => 'subscriber',
+
+			// Memberships
+			'block_frontend'                     => 0,
+			'block_frontend_grace_period'        => 0,
+			'enable_multiple_memberships'        => 0,
+			'enable_multiple_sites'              => 0,
+			'block_sites_on_downgrade'           => 'none',
+			'move_posts_on_downgrade'            => 'none',
+			'emulated_post_types'                => [],
+
+			// Sites
+			'enable_visits_limiting'             => 1,
+			'enable_screenshot_generator'        => 1,
+			'menu_items_plugin'                  => 1,
+			'add_new_users'                      => 1,
+			'allow_template_switching'           => 1,
+			'allow_own_site_as_template'         => 0,
+			'copy_media'                         => 1,
+			'stop_template_indexing'             => 0,
+
+			// Payment Gateways
+			'force_auto_renew'                   => 1,
+			'allow_trial_without_payment_method' => 0,
+			'attach_invoice_pdf'                 => 1,
+			'invoice_numbering_scheme'           => 'reference_code',
+			'next_invoice_number'                => '1',
+			'invoice_prefix'                     => '',
+
+			// Emails (registered via hooks but commonly queried)
+			'from_name'                          => '',
+			'from_email'                         => '',
+
+			// Domain Mapping (registered via hooks but commonly queried)
+			'enable_domain_mapping'              => false,
+			'custom_domains'                     => false,
+			'domain_mapping_instructions'        => '',
+
+			// SSO (registered via hooks)
+			'enable_sso'                         => 1,
+
+			// Other
+			'hide_tours'                         => 0,
+			'disable_image_zoom'                 => 0,
+			'error_logging_level'                => 'default',
+			'security_mode'                      => 0,
+			'uninstall_wipe_tables'              => 0,
+
+			// Whitelabel (registered via hooks)
+			'rename_site_plural'                 => '',
+			'rename_site_singular'               => '',
+			'rename_wordpress'                   => '',
+
+			// Maintenance mode (registered via hooks)
+			'maintenance_mode'                   => false,
+
+			// Notifications
+			'hide_notifications_subsites'        => false,
+
+			// Taxes
+			'enable_taxes'                       => false,
+
+			// Checkout-related
+			'default_pricing_option'             => 1,
+			'allowed_countries'                  => [],
+			'trial'                              => 0,
+
+			// Manual gateway
+			'manual_payment_instructions'        => '',
+
+			// Event manager
+			'saving_type'                        => [],
+
+			// Jumper
+			'jumper_custom_links'                => '',
+
+			// Limits
+			'limits_and_quotas'                  => [],
+
+			// Legacy pricing toggles
+			'enable_price_3'                     => true,
+			'enable_price_12'                    => true,
+		];
+	}
+
+	/**
+	 * Returns a lightweight list of section slugs and titles for use
+	 * in the admin bar and other places that don't need full field definitions.
+	 *
+	 * This avoids triggering default_sections() and all the expensive
+	 * field registration that comes with it.
+	 *
+	 * @since 2.5.0
+	 * @return array<string, array{title: string, icon: string}>
+	 */
+	public function get_section_names(): array {
+
+		$core_sections = [
+			'general'                => [
+				'title' => __('General', 'ultimate-multisite'),
+				'icon'  => 'dashicons-wu-cog',
+			],
+			'login-and-registration' => [
+				'title' => __('Login & Registration', 'ultimate-multisite'),
+				'icon'  => 'dashicons-wu-key',
+			],
+			'memberships'            => [
+				'title' => __('Memberships', 'ultimate-multisite'),
+				'icon'  => 'dashicons-wu-infinity',
+			],
+			'sites'                  => [
+				'title' => __('Sites', 'ultimate-multisite'),
+				'icon'  => 'dashicons-wu-browser',
+			],
+			'payment-gateways'       => [
+				'title' => __('Payments', 'ultimate-multisite'),
+				'icon'  => 'dashicons-wu-credit-card',
+			],
+			'emails'                 => [
+				'title' => __('Emails', 'ultimate-multisite'),
+				'icon'  => 'dashicons-wu-email',
+			],
+			'domain-mapping'         => [
+				'title' => __('Domain Mapping', 'ultimate-multisite'),
+				'icon'  => 'dashicons-wu-link',
+			],
+			'sso'                    => [
+				'title' => __('Single Sign-On', 'ultimate-multisite'),
+				'icon'  => 'dashicons-wu-add-user',
+			],
+			'integrations'           => [
+				'title' => __('Integrations', 'ultimate-multisite'),
+				'icon'  => 'dashicons-wu-power-plug',
+			],
+			'import-export'          => [
+				'title' => __('Import/Export', 'ultimate-multisite'),
+				'icon'  => 'dashicons-wu-download',
+				'order' => 995,
+			],
+			'other'                  => [
+				'title' => __('Other Options', 'ultimate-multisite'),
+				'icon'  => 'dashicons-wu-switch',
+				'order' => 1000,
+			],
+		];
+
+		/**
+		 * Allows addons to register their section names without triggering
+		 * the full field registration in default_sections().
+		 *
+		 * @since 2.5.0
+		 * @param array $sections Section slug => array with 'title', 'icon', and optionally 'addon' => true.
+		 */
+		return apply_filters('wu_settings_section_names', $core_sections);
+	}
+
 	/**
 	 * Tries to determine the location of the company based on the admin IP.
 	 *
diff --git a/inc/class-whitelabel.php b/inc/class-whitelabel.php
index 71511db2..726e3e96 100644
--- a/inc/class-whitelabel.php
+++ b/inc/class-whitelabel.php
@@ -88,9 +88,9 @@ public function hooks(): void {
 			add_action('network_admin_menu', [$this, 'remove_sites_admin_menu']);
 		}
 
-		if (wu_get_setting('rename_site_plural') ||
-			wu_get_setting('rename_site_singular') ||
-			wu_get_setting('rename_wordpress')
+		if (wu_get_setting('rename_site_plural', '') ||
+			wu_get_setting('rename_site_singular', '') ||
+			wu_get_setting('rename_wordpress', '')
 		) {
 			$this->allowed_domains = apply_filters(
 				'wu_replace_text_allowed_domains',
@@ -102,21 +102,21 @@ public function hooks(): void {
 			);
 
 			$search_and_replace = [];
-			$site_plural        = wu_get_setting('rename_site_plural');
+			$site_plural        = wu_get_setting('rename_site_plural', '');
 
 			if ($site_plural) {
 				$search_and_replace['sites'] = strtolower((string) $site_plural);
 				$search_and_replace['Sites'] = ucfirst((string) $site_plural);
 			}
 
-			$site_singular = wu_get_setting('rename_site_singular');
+			$site_singular = wu_get_setting('rename_site_singular', '');
 
 			if ($site_singular) {
 				$search_and_replace['site'] = strtolower((string) $site_singular);
 				$search_and_replace['Site'] = ucfirst((string) $site_singular);
 			}
 
-			$wordpress = wu_get_setting('rename_wordpress');
+			$wordpress = wu_get_setting('rename_wordpress', '');
 
 			if ($wordpress) {
 				$search_and_replace['wordpress'] = strtolower((string) $wordpress);
diff --git a/inc/deprecated/deprecated.php b/inc/deprecated/deprecated.php
index 388f6d4c..c4c19035 100644
--- a/inc/deprecated/deprecated.php
+++ b/inc/deprecated/deprecated.php
@@ -271,8 +271,8 @@ public function send_mail($to, $subject, $content, $html = true, $shortcodes = [
 		_deprecated_function(__METHOD__, '2.0.0', 'wu_send_mail()');
 
 		$from = [
-			'name'  => wu_get_setting('from_name'),
-			'email' => wu_get_setting('from_email'),
+			'name'  => wu_get_setting('from_name', ''),
+			'email' => wu_get_setting('from_email', ''),
 		];
 
 		/*
diff --git a/inc/functions/settings.php b/inc/functions/settings.php
index fc559285..f30536ba 100644
--- a/inc/functions/settings.php
+++ b/inc/functions/settings.php
@@ -173,7 +173,7 @@ function wu_get_network_logo($size = 'full') {
  */
 function wu_get_network_logo_attachement_id() {
 
-	$settings_logo = wu_get_setting('company_logo');
+	$settings_logo = wu_get_setting('company_logo', '');
 
 	if ($settings_logo) {
 		return $settings_logo;
diff --git a/inc/gateways/class-manual-gateway.php b/inc/gateways/class-manual-gateway.php
index 07b591a4..623ef28b 100644
--- a/inc/gateways/class-manual-gateway.php
+++ b/inc/gateways/class-manual-gateway.php
@@ -400,7 +400,7 @@ public function add_payment_instructions_block($payment, $membership, $customer)
 
 					<div class="wu-bg-gray-100 wu-rounded wu-p-4">
 
-						<?php echo do_shortcode(wu_get_setting('manual_payment_instructions')); ?>
+						<?php echo do_shortcode(wu_get_setting('manual_payment_instructions', '')); ?>
 
 					</div>
 
diff --git a/inc/helpers/class-sender.php b/inc/helpers/class-sender.php
index 8d49a6f2..5c0e3f92 100644
--- a/inc/helpers/class-sender.php
+++ b/inc/helpers/class-sender.php
@@ -33,8 +33,8 @@ public static function parse_args($args = []) {
 
 		$default_args = [
 			'from'        => [
-				'name'  => wu_get_setting('from_name'),
-				'email' => wu_get_setting('from_email'),
+				'name'  => wu_get_setting('from_name', ''),
+				'email' => wu_get_setting('from_email', ''),
 			],
 			'content'     => '',
 			'subject'     => '',
@@ -63,8 +63,8 @@ public static function send_mail($from = [], $to = [], $args = []) {
 
 		if ( ! $from) {
 			$from = [
-				'email' => wu_get_setting('from_email'),
-				'name'  => wu_get_setting('from_name'),
+				'email' => wu_get_setting('from_email', ''),
+				'name'  => wu_get_setting('from_name', ''),
 			];
 		}
 
diff --git a/inc/helpers/validation-rules/class-site-template.php b/inc/helpers/validation-rules/class-site-template.php
index 1d4ef7c5..a28135f6 100644
--- a/inc/helpers/validation-rules/class-site-template.php
+++ b/inc/helpers/validation-rules/class-site-template.php
@@ -62,7 +62,7 @@ public function check($template_id) : bool { // phpcs:ignore
 		}
 
 		if ($site->get_type() === Site_Type::CUSTOMER_OWNED) {
-			if (! wu_get_setting('allow_own_site_as_template')) {
+			if (! wu_get_setting('allow_own_site_as_template', false)) {
 				$this->message = __('You can not use your sites as template', 'ultimate-multisite');
 
 				return false;
diff --git a/inc/installers/class-default-content-installer.php b/inc/installers/class-default-content-installer.php
index 92a8b792..ed7b6fae 100644
--- a/inc/installers/class-default-content-installer.php
+++ b/inc/installers/class-default-content-installer.php
@@ -125,7 +125,7 @@ protected function done_creating_emails() {
 	 */
 	protected function done_creating_login_page() {
 
-		$page_id = wu_get_setting('default_login_page');
+		$page_id = wu_get_setting('default_login_page', 0);
 
 		if ( ! $page_id) {
 			return false;
diff --git a/inc/managers/class-customer-manager.php b/inc/managers/class-customer-manager.php
index c4c25463..1d2f604e 100644
--- a/inc/managers/class-customer-manager.php
+++ b/inc/managers/class-customer-manager.php
@@ -337,7 +337,7 @@ public function maybe_verify_email_address(): void {
 	 */
 	public function maybe_add_to_main_site($customer, $checkout): void {
 
-		if ( ! wu_get_setting('add_users_to_main_site')) {
+		if ( ! wu_get_setting('add_users_to_main_site', false)) {
 			return;
 		}
 
diff --git a/inc/managers/class-domain-manager.php b/inc/managers/class-domain-manager.php
index 9d6a3d8d..80a89053 100644
--- a/inc/managers/class-domain-manager.php
+++ b/inc/managers/class-domain-manager.php
@@ -581,7 +581,7 @@ public function get_domain_mapping_instructions() {
 
 		global $current_site;
 
-		$instructions = wu_get_setting('domain_mapping_instructions');
+		$instructions = wu_get_setting('domain_mapping_instructions', '');
 
 		if ( ! $instructions) {
 			$instructions = $this->default_domain_mapping_instructions();
diff --git a/inc/managers/class-email-manager.php b/inc/managers/class-email-manager.php
index 852a8f75..6857829a 100644
--- a/inc/managers/class-email-manager.php
+++ b/inc/managers/class-email-manager.php
@@ -104,8 +104,8 @@ public function send_system_email($slug, $payload): void {
 		);
 
 		$original_from = [
-			'name'  => wu_get_setting('from_name'),
-			'email' => wu_get_setting('from_email'),
+			'name'  => wu_get_setting('from_name', ''),
+			'email' => wu_get_setting('from_email', ''),
 		];
 
 		if (empty($all_emails)) {
diff --git a/inc/managers/class-notification-manager.php b/inc/managers/class-notification-manager.php
index bd777905..c9a548c8 100644
--- a/inc/managers/class-notification-manager.php
+++ b/inc/managers/class-notification-manager.php
@@ -54,7 +54,7 @@ public function init(): void {
 	 */
 	public function hide_notifications_subsites(): void {
 
-		if ( ! wu_get_setting('hide_notifications_subsites')) {
+		if ( ! wu_get_setting('hide_notifications_subsites', false)) {
 			return;
 		}
 
diff --git a/inc/tax/class-dashboard-taxes-tab.php b/inc/tax/class-dashboard-taxes-tab.php
index 727bab61..e0981585 100644
--- a/inc/tax/class-dashboard-taxes-tab.php
+++ b/inc/tax/class-dashboard-taxes-tab.php
@@ -46,7 +46,7 @@ public function __construct() {
 	 */
 	protected function is_enabled() {
 
-		return wu_get_setting('enable_taxes');
+		return wu_get_setting('enable_taxes', false);
 	}
 
 	/**
diff --git a/inc/tax/class-tax.php b/inc/tax/class-tax.php
index f786c69a..322f0bd9 100644
--- a/inc/tax/class-tax.php
+++ b/inc/tax/class-tax.php
@@ -370,7 +370,7 @@ public function render_taxes_side_panel(): void {
 					}
 				});
 			});',
-			wp_json_encode(wu_get_setting('enable_taxes'))
+			wp_json_encode(wu_get_setting('enable_taxes', false))
 		);
 
 		wp_add_inline_script('wu-vue', $inline_script);
diff --git a/inc/traits/trait-wp-ultimo-plan-deprecated.php b/inc/traits/trait-wp-ultimo-plan-deprecated.php
index 6b3d5e36..4e4dea48 100644
--- a/inc/traits/trait-wp-ultimo-plan-deprecated.php
+++ b/inc/traits/trait-wp-ultimo-plan-deprecated.php
@@ -196,7 +196,7 @@ public function get_pricing_table_lines() {
 		 * Site, Disk Space and Trial
 		 * Gets the Disk Space and Sites to be displayed on the pricing table options
 		 */
-		if (wu_get_setting('enable_multiple_sites') && $this->should_display_quota_on_pricing_tables('sites')) {
+		if (wu_get_setting('enable_multiple_sites', false) && $this->should_display_quota_on_pricing_tables('sites')) {
 			$is_unlimited = (int) $this->get_limitations()->sites->get_limit() === 0 || ! $this->get_limitations()->sites->is_enabled();
 			$value        = $is_unlimited ? __('Unlimited', 'ultimate-multisite') : $this->get_limitations()->sites->get_limit();
 
@@ -232,7 +232,7 @@ public function get_pricing_table_lines() {
 		/**
 		 * Display Trial, if some
 		 */
-		$trial_days      = wu_get_setting('trial');
+		$trial_days      = wu_get_setting('trial', 0);
 		$trial_days_plan = $this->get_trial_duration();
 
 		if ($trial_days > 0 || $trial_days_plan) {
diff --git a/inc/ui/class-domain-mapping-element.php b/inc/ui/class-domain-mapping-element.php
index fea0c0f6..93fe6a36 100644
--- a/inc/ui/class-domain-mapping-element.php
+++ b/inc/ui/class-domain-mapping-element.php
@@ -221,7 +221,7 @@ public function init(): void {
 			$maybe_limit_domain_mapping = $this->site->get_limitations()->domain_mapping->is_enabled();
 		}
 
-		if ( ! $this->site || ! wu_get_setting('enable_domain_mapping') || ! wu_get_setting('custom_domains') || ! $maybe_limit_domain_mapping) {
+		if ( ! $this->site || ! wu_get_setting('enable_domain_mapping', false) || ! wu_get_setting('custom_domains', false) || ! $maybe_limit_domain_mapping) {
 			$this->set_display(false);
 		}
 
diff --git a/inc/ui/class-jumper.php b/inc/ui/class-jumper.php
index db15aa42..298201b5 100644
--- a/inc/ui/class-jumper.php
+++ b/inc/ui/class-jumper.php
@@ -156,7 +156,7 @@ public function get_user_custom_links() {
 
 		$treated_lines = [];
 
-		$saved_links = wu_get_setting('jumper_custom_links');
+		$saved_links = wu_get_setting('jumper_custom_links', '');
 
 		$lines = explode(PHP_EOL, (string) $saved_links);
 
diff --git a/inc/ui/class-limits-element.php b/inc/ui/class-limits-element.php
index 89d6f20d..35b882dc 100644
--- a/inc/ui/class-limits-element.php
+++ b/inc/ui/class-limits-element.php
@@ -266,7 +266,7 @@ public function output($atts, $content = null): void {
 		 */
 		$post_types = apply_filters('wu_get_post_types', $post_types);
 
-		$items_to_display = wu_get_setting('limits_and_quotas');
+		$items_to_display = wu_get_setting('limits_and_quotas', []);
 
 		$atts['site']             = $this->site;
 		$atts['post_types']       = $post_types;
diff --git a/patches/mpdf-psr-http-message-shim-php8-compat.patch b/patches/mpdf-psr-http-message-shim-php8-compat.patch
new file mode 100644
index 00000000..02774511
--- /dev/null
+++ b/patches/mpdf-psr-http-message-shim-php8-compat.patch
@@ -0,0 +1,137 @@
+--- a/vendor/mpdf/psr-http-message-shim/src/Request.php
++++ b/vendor/mpdf/psr-http-message-shim/src/Request.php
+@@ -66,7 +66,7 @@ class Request implements \Psr\Http\Message\RequestInterface
+ 		}
+ 	}
+ 
+-	public function getRequestTarget()
++	public function getRequestTarget(): string
+ 	{
+ 		if ($this->requestTarget !== null) {
+ 			return $this->requestTarget;
+@@ -83,7 +83,7 @@ class Request implements \Psr\Http\Message\RequestInterface
+ 		return $target;
+ 	}
+ 
+-	public function withRequestTarget($requestTarget)
++	public function withRequestTarget(string $requestTarget): \Psr\Http\Message\RequestInterface
+ 	{
+ 		if (preg_match('#\s#', $requestTarget)) {
+ 			throw new \InvalidArgumentException('Invalid request target provided; cannot contain whitespace');
+@@ -95,11 +95,11 @@ class Request implements \Psr\Http\Message\RequestInterface
+ 		return $new;
+ 	}
+ 
+-	public function getMethod()
++	public function getMethod(): string
+ 	{
+ 		return $this->method;
+ 	}
+ 
+-	public function withMethod($method)
++	public function withMethod(string $method): \Psr\Http\Message\RequestInterface
+ 	{
+ 		$new = clone $this;
+ 		$new->method = $method;
+@@ -107,11 +107,11 @@ class Request implements \Psr\Http\Message\RequestInterface
+ 		return $new;
+ 	}
+ 
+-	public function getUri()
++	public function getUri(): \Psr\Http\Message\UriInterface
+ 	{
+ 		return $this->uri;
+ 	}
+ 
+-	public function withUri(UriInterface $uri, $preserveHost = false)
++	public function withUri(\Psr\Http\Message\UriInterface $uri, bool $preserveHost = false): \Psr\Http\Message\RequestInterface
+ 	{
+ 		if ($uri === $this->uri) {
+ 			return $this;
+@@ -152,11 +152,11 @@ class Request implements \Psr\Http\Message\RequestInterface
+ 		$this->headers = [$header => [$host]] + $this->headers;
+ 	}
+ 
+-	public function getProtocolVersion()
++	public function getProtocolVersion(): string
+ 	{
+ 		return $this->protocol;
+ 	}
+ 
+-	public function withProtocolVersion($version)
++	public function withProtocolVersion(string $version): \Psr\Http\Message\MessageInterface
+ 	{
+ 		if ($this->protocol === $version) {
+ 			return $this;
+@@ -168,15 +168,15 @@ class Request implements \Psr\Http\Message\RequestInterface
+ 		return $new;
+ 	}
+ 
+-	public function getHeaders()
++	public function getHeaders(): array
+ 	{
+ 		return $this->headers;
+ 	}
+ 
+-	public function hasHeader($header)
++	public function hasHeader(string $header): bool
+ 	{
+ 		return isset($this->headerNames[strtolower($header)]);
+ 	}
+ 
+-	public function getHeader($header)
++	public function getHeader(string $header): array
+ 	{
+ 		$header = strtolower($header);
+ 
+@@ -192,11 +192,11 @@ class Request implements \Psr\Http\Message\RequestInterface
+ 		return $this->headers[$header];
+ 	}
+ 
+-	public function getHeaderLine($header)
++	public function getHeaderLine(string $header): string
+ 	{
+ 		return implode(', ', $this->getHeader($header));
+ 	}
+ 
+-	public function withHeader($header, $value)
++	public function withHeader(string $header, $value): \Psr\Http\Message\MessageInterface
+ 	{
+ 		if (!is_array($value)) {
+ 			$value = [$value];
+@@ -216,7 +216,7 @@ class Request implements \Psr\Http\Message\RequestInterface
+ 		return $new;
+ 	}
+ 
+-	public function withAddedHeader($header, $value)
++	public function withAddedHeader(string $header, $value): \Psr\Http\Message\MessageInterface
+ 	{
+ 		if (!is_array($value)) {
+ 			$value = [$value];
+@@ -237,7 +237,7 @@ class Request implements \Psr\Http\Message\RequestInterface
+ 		return $new;
+ 	}
+ 
+-	public function withoutHeader($header)
++	public function withoutHeader(string $header): \Psr\Http\Message\MessageInterface
+ 	{
+ 		$normalized = strtolower($header);
+ 
+@@ -253,7 +253,7 @@ class Request implements \Psr\Http\Message\RequestInterface
+ 		return $new;
+ 	}
+ 
+-	public function getBody()
++	public function getBody(): \Psr\Http\Message\StreamInterface
+ 	{
+ 		if (!$this->stream) {
+ 			$this->stream = Stream::create('');
+@@ -263,7 +263,7 @@ class Request implements \Psr\Http\Message\RequestInterface
+ 		return $this->stream;
+ 	}
+ 
+-	public function withBody(StreamInterface $body)
++	public function withBody(\Psr\Http\Message\StreamInterface $body): \Psr\Http\Message\MessageInterface
+ 	{
+ 		if ($body === $this->stream) {
+ 			return $this;
diff --git a/views/broadcast/emails/base.php b/views/broadcast/emails/base.php
index 78d21ef6..612d2221 100644
--- a/views/broadcast/emails/base.php
+++ b/views/broadcast/emails/base.php
@@ -93,7 +93,7 @@
 							<tr style="">
 								<td style=" text-align: center;">
 									<p style="font-family: <?php echo esc_attr($template_settings['footer_font']); ?>; font-size: 12px; line-height: 1.6em; color: <?php echo esc_attr($template_settings['footer_color']); ?>; font-weight: normal; margin: 0 0 10px; padding: 0; text-align: <?php echo esc_attr($template_settings['footer_align']); ?>">
-										<strong><?php echo esc_html(wu_get_setting('company_name')); ?></strong><br>
+										<strong><?php echo esc_html(wu_get_setting('company_name', '')); ?></strong><br>
 										<?php
 										$company_address = wu_get_setting('company_address', '');
 										echo is_string($company_address) ? nl2br(esc_html($company_address)) : '';
diff --git a/views/dashboard-widgets/my-sites.php b/views/dashboard-widgets/my-sites.php
index 27896692..da9a04ab 100644
--- a/views/dashboard-widgets/my-sites.php
+++ b/views/dashboard-widgets/my-sites.php
@@ -6,7 +6,7 @@
  */
 defined('ABSPATH') || exit;
 
-$add_new_url = wu_get_setting('enable_multiple_sites') ? $element->get_new_site_url() : wu_get_registration_url();
+$add_new_url = wu_get_setting('enable_multiple_sites', false) ? $element->get_new_site_url() : wu_get_registration_url();
 
 // Redirect back to this page after create the site
 $add_new_url = add_query_arg(
@@ -16,7 +16,7 @@
 	$add_new_url
 );
 
-$show_add_new = wu_get_setting('enable_multiple_sites') || wu_get_setting('enable_multiple_memberships');
+$show_add_new = wu_get_setting('enable_multiple_sites', false) || wu_get_setting('enable_multiple_memberships', false);
 
 $show_add_new = apply_filters('wp_ultimo_my_sites_show_add_new', $show_add_new);