After network activation of GiveWP core plugin version 2.33.2 on a multisite WP install running on PHP 8.0, visiting the dashboard of a subsite (not the main site) produced: Warning: Undefined array key "thousands_separator" in .../wp-content/plugins/give/includes/admin/upgrades/upgrade-functions.php on line 1362 Warning: Undefined array key "decimal_separator" in .../wp-content/plugins/give/includes/admin/upgrades/upgrade-functions.php on line 1362 Warning: Undefined array key "currency" in .../wp-content/plugins/give/includes/admin/upgrades/upgrade-functions.php on line 1626 Warning: Undefined array key "gateways" in .../wp-content/plugins/give/src/PaymentGateways/Gateways/PayPalStandard/Migrations/SetPayPalStandardGatewayId.php on line 27 Fatal error: Uncaught TypeError: array_key_exists(): Argument #2 ($array) must be of type array, null given in .../wp-content/plugins/give/src/PaymentGateways/Gateways/PayPalStandard/Migrations/SetPayPalStandardGatewayId.php:30 Stack trace: #0 .../wp-content/plugins/give/src/PaymentGateways/Gateways/PayPalStandard/Migrations/SetPayPalStandardGatewayId.php(30): array_key_exists('paypal-standard', NULL) #1 .../wp-content/plugins/give/src/Framework/Migrations/MigrationsRunner.php(113): Give\PaymentGateways\Gateways\PayPalStandard\Migrations\SetPayPalStandardGatewayId->run() #2 [internal function]: Give\Framework\Migrations\MigrationsRunner->run('') #3 .../wp-content/plugins/give/src/Helpers/Hooks.php(43): call_user_func_array(Array, Array) #4 .../wp-includes/class-wp-hook.php(310): Give\Helpers\Hooks::Give\Helpers\{closure}('') #5 .../wp-includes/class-wp-hook.php(334): WP_Hook->apply_filters(NULL, Array) #6 .../wp-includes/plugin.php(517): WP_Hook->do_action(Array) #7 .../wp-admin/admin.php(175): do_action('admin_init') #8 .../wp-admin/index.php(10): require_once('/Users/david/Lo...') #9 {main} thrown in .../wp-content/plugins/give/src/PaymentGateways/Gateways/PayPalStandard/Migrations/SetPayPalStandardGatewayId.php on line 30 Subsequent attempts to visit the subsite or activate the plugin at the subsite level produced: Warning: Undefined array key "gateways" in .../wp-content/plugins/give/src/PaymentGateways/Gateways/PayPalStandard/Migrations/SetPayPalStandardGatewayId.php on line 27 Fatal error: Uncaught TypeError: array_key_exists(): Argument #2 ($array) must be of type array, null given in .../wp-content/plugins/give/src/PaymentGateways/Gateways/PayPalStandard/Migrations/SetPayPalStandardGatewayId.php:30 Stack trace: #0 .../wp-content/plugins/give/src/PaymentGateways/Gateways/PayPalStandard/Migrations/SetPayPalStandardGatewayId.php(30): array_key_exists('paypal-standard', NULL) #1 .../wp-content/plugins/give/src/Framework/Migrations/MigrationsRunner.php(113): Give\PaymentGateways\Gateways\PayPalStandard\Migrations\SetPayPalStandardGatewayId->run() #2 [internal function]: Give\Framework\Migrations\MigrationsRunner->run('') #3 .../wp-content/plugins/give/src/Helpers/Hooks.php(43): call_user_func_array(Array, Array) #4 .../wp-includes/class-wp-hook.php(310): Give\Helpers\Hooks::Give\Helpers\{closure}('') #5 .../wp-includes/class-wp-hook.php(334): WP_Hook->apply_filters(NULL, Array) #6 .../wp-includes/plugin.php(517): WP_Hook->do_action(Array) #7 .../wp-content/plugins/give/includes/install.php(109): do_action('give_upgrades') #8 .../wp-content/plugins/give/includes/install.php(49): give_run_install() #9 .../wp-content/plugins/give/give.php(410): give_install() #10 .../wp-includes/class-wp-hook.php(310): Give->install('') #11 .../wp-includes/class-wp-hook.php(334): WP_Hook->apply_filters('', Array) #12 .../wp-includes/plugin.php(517): WP_Hook->do_action(Array) #13 .../wp-admin/plugins.php(194): do_action('activate_give/g...') #14 {main} thrown in .../wp-content/plugins/give/src/PaymentGateways/Gateways/PayPalStandard/Migrations/SetPayPalStandardGatewayId.php on line 30 Temporary workaround seems to be to revert to PHP 7.4.x, activate the plugin at the subsite level, run the DB updater, then it seems to be possible to revert back to PHP 8.0.x without further errors.