When you update the Woocommerce, WordPress announces that the Mercado Pago payment has a conflict.
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SOLUTION
Surely, you can fix that errors by hard code on plugin Mecardo Pago,
file: \wp-content\plugins\woocommerce-mercadopago\includes\module\preference\WC_WooMercadoPago_PreferenceAbstract. Then, at line 184 or around, find and replace:
$product = new WC_product($item[‘product_id’]);
by
$product = wc_get_product($item[‘product_id’]);
That function has no hook, so we can’t intervene to override.
Read more: LearnPress Payment Settings: The All-in-one tutorial