Devtard

This plugin overrides default date and time of edited posts with dynamically calculated custom values. This is useful especially when scheduling posts; the plugin can, for example, automatically generate new post dates by incrementing the current most future post date by a specified number of days.
Calculated custom date and time will automatically replace default values after clicking the “Edit” link next to “Publish immediately” in the post editor’s Publish module.
<h4>Features</h4>
<ul>
<li>Date/time values usable as a reference: current date/time, oldest or most future post date/time; specific time of day</li>
<li>Date/time of reference can be increased or decreased by a specific number of days/minutes</li>
<li>Configurable post types and statuses of analyzed and affected posts</li>
</ul>
See <a href="https://wordpress.org/plugins/automatic-post-date-filler/screenshots/" rel="ugc">Screenshots</a> for more information.

Automatic Post Date Filler

Automatically sets custom date and time when editing posts.

Takashi Murakami

If you are not logged in, it will not hide the current public posts. ( Only one generation, but allows the future of the article published. ) 
公開記事を更新（予約投稿）した状態であっても、..訪問者が予約投稿前の記事を閲覧できるようになる

Fixed Future Posts

Plug-in ( Fixed Future Posts ) for the WordPress.

Automatic Post Date Filler vs Fixed Future Posts