Piotr

Problem:
If you're using WPML with ClassicPress and have encountered a fatal error after updating to ClassicPress version 2.0.0, which indicates an undefined function

register_block_type()

, we have a workaround for you.

Solution:
To prevent the fatal error, follow these steps:
1. Navigate to

wp-content/plugins/sitepress-multilingual-cms/classes/block-editor/class-wpml-block-editor-helper.php

2. Locate line 31 and just before the

return true;

statement,
3. Insert the following condition:

if ( ! function_exists( 'register_block_type' ) ) {
	return false;
}

The issue is going to be handled in future versions of WPML.

Please note that this solution might be irrelevant if it's outdated or not applicable to your case. We highly recommend checking the related known issues, verifying the version of the permanent fix, and confirming that you have installed the latest versions of themes and plugins. If the issue persists, please open a new support ticket with us.