Pre-filter the return value of get_lastpostmodified() before the query is run.

$lastpostmodified string|false

The most recent time that a post was modified, in 'Y-m-d H:i:s' format, or false. Returning anything other than false will short-circuit the function.

$timezone string

Location to use for getting the post modified date.
See get_lastpostdate() for accepted $timezone values.

More Arguments from get_lastpostdate( ... $timezone )

The timezone for the timestamp. Accepts 'server', 'blog', or 'gmt'.
'server' uses the server's internal timezone.
'blog' uses the post_date field, which proxies to the timezone set for the site.
'gmt' uses the post_date_gmt field.
Default 'server'.

$post_type string

The post type to check.

File: wp-includes/post.php. View all references

$lastpostmodified = apply_filters( 'pre_get_lastpostmodified', false, $timezone, $post_type );