Keep the last modified date unchanged for minor post updates.
Plugin Tag: last-modified
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LH Add Headers
Adds the ETag, Last-Modified, and if appropriate 304 headers to HTTP responses generated by WordPress for more efficient caching.
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TW Post Modifier Tracker
Adds a Last Modified column in WordPress admin showing the date, time, and user of the last update for posts, pages, products and custom types.
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Smart WordPress
Optimize the caching behavior of your Website the easy way and reload pages only if something has been changed.
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Products and Orders Last Modified for WC REST API
Retrieve Last Modified Products and Orders via WooCommerce REST API
