# Fix Old Subsite URLs After Domain Mapping

> Rewrites links and image URLs that still point at a site's old network address (like example.com/shop/) to its mapped domain when content is displayed.

- Type: PHP
- Runs: Frontend only
- Category: [Multisite](https://wpide.com/library/category/multisite/)
- Tags: domain-mapping, urls, mixed-content
- Author: WPIDE Team
- Installs: 0
- Updated: 2026-10-28
- Page: https://wpide.com/library/ms-fix-mapped-domain-urls/

## Code

```php
if ( ! is_multisite() ) {
    return;
}

$wpide_old_urls = array( // Blog ID => old address (without trailing slash).
    // 2 => 'https://network.example.com/shop',
);

$wpide_id = get_current_blog_id();

if ( empty( $wpide_old_urls[ $wpide_id ] ) ) {
    return;
}

$wpide_old = untrailingslashit( $wpide_old_urls[ $wpide_id ] );
$wpide_new = untrailingslashit( home_url() );

if ( $wpide_old === $wpide_new ) {
    return;
}

$wpide_fix = function ( $content ) use ( $wpide_old, $wpide_new ) {
    if ( ! is_string( $content ) || false === strpos( $content, $wpide_old ) ) {
        return $content;
    }

    $variants = array( $wpide_old, set_url_scheme( $wpide_old, 'http' ), str_replace( '/', '\/', $wpide_old ) );

    return str_replace( $variants, array( $wpide_new, $wpide_new, str_replace( '/', '\/', $wpide_new ) ), $content );
};

foreach ( array( 'the_content', 'the_excerpt', 'widget_text', 'widget_block_content', 'wp_get_attachment_url' ) as $wpide_hook ) {
    add_filter( $wpide_hook, $wpide_fix, 99 );
}
```

## Notes

Set $wpide_old_urls per blog ID. This fixes display only; run a search-replace later to update the database permanently.

## How to use it

Install the free WPIDE plugin (https://wordpress.org/plugins/wpide/), find "Fix Old Subsite URLs After Domain Mapping" in its snippet library and add it in one click; or create a new PHP snippet in WPIDE (or any code snippets plugin) and paste the code above. More snippets: https://wpide.com/library/