Title: If-Modified-Since HTTP header
Last modified: August 21, 2017

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# If-Modified-Since HTTP header

 *  Resolved [mikeldev](https://wordpress.org/support/users/mikeldev/)
 * (@mikeldev)
 * [8 years, 8 months ago](https://wordpress.org/support/topic/if-modified-since-http-header/)
 * Testing my site with [varvy SEO tool](https://varvy.com/) I see it complains 
   about If-Modified-Since HTTP header.
 * ![](http://imgur.com/a/MYMgV)
 * After [reading about it ](https://varvy.com/ifmodified.html)I see it is a header
   use by e.g. Google to tell them, _hey you don’t need to scan it again_.
 * I [saw how to add the header to WP](https://wordpress.stackexchange.com/a/172968/123273),
   but this functionality is suppose to be in a plugin and not on the theme.
 * Since Autoptimize already knows when was the last modification (and cache) it
   might be _easy/easier_ to implement.
 * Thank you,
    Mikel

Viewing 3 replies - 1 through 3 (of 3 total)

 *  Plugin Author [Optimizing Matters](https://wordpress.org/support/users/optimizingmatters/)
 * (@optimizingmatters)
 * [8 years, 8 months ago](https://wordpress.org/support/topic/if-modified-since-http-header/#post-9426770)
 * hey [@mikeldev](https://wordpress.org/support/users/mikeldev/);
 * > Since Autoptimize already knows when was the last modification (and cache) 
   > it might be easy/easier to implement.
 * Afraid AO would only know the creation date of the autoptimized CSS/ JS-files.
   The logic place where If-Modified-Since could be added would rather be on a page
   cache plugin level (and I suppose some do come with that flag)?
 * hope this clarifies,
    frank
 *  Thread Starter [mikeldev](https://wordpress.org/support/users/mikeldev/)
 * (@mikeldev)
 * [8 years, 8 months ago](https://wordpress.org/support/topic/if-modified-since-http-header/#post-9426891)
 * Oh yes,
 * I wanted to ask this in comet cache plugin but I don’t know how I did here.
    
   I just confused for a second the plugins. Apologies!
 *  Plugin Author [Optimizing Matters](https://wordpress.org/support/users/optimizingmatters/)
 * (@optimizingmatters)
 * [8 years, 8 months ago](https://wordpress.org/support/topic/if-modified-since-http-header/#post-9426907)
 * no problem [@mikeldev](https://wordpress.org/support/users/mikeldev/) 🙂

Viewing 3 replies - 1 through 3 (of 3 total)

The topic ‘If-Modified-Since HTTP header’ is closed to new replies.

 * ![](https://ps.w.org/autoptimize/assets/icon-256X256.png?rev=2211608)
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 * 3 replies
 * 2 participants
 * Last reply from: [Optimizing Matters](https://wordpress.org/support/users/optimizingmatters/)
 * Last activity: [8 years, 8 months ago](https://wordpress.org/support/topic/if-modified-since-http-header/#post-9426907)
 * Status: resolved