Is RSS Item pubDate Field Required (for Calibre to process a "News" Feed)?

[readabit]

This is actually for a daily readings feed (not public, currently building), where on given date when the feed is requested it will return readings for today and subsequent days (ie, tomorrow, the next day and so on). So for various reasons the feed will never display "historical" data, only today and forward.

I've read that using future pubDate on RSS Items may not always work properly (though I don't know how Calibre would handle), so I'm thinking of just creating the RSS feed without pubDate for each item. The feed would output items with today being first, then tomorrow, then the next day, on down the page/feed.

The end goal is to point the Calibre News functionality to this feed to periodically create an epub of the current and future readings. So I'm just wondering how essential the RSS Item pubDate field is for Calibre, whether Calibre will work fine without that data, and how Calibre would handle using future pubDate values (eg, for tomorrow's entry, and the next day, and so on)?

Thanks in advance for any input!

[kovidgoyal]

publication dates are used to exlude articles that are too old, I doubt future dated articles will have any impact, see the oldest_article setting in the recipe class.

[readabit]

Okay, great! So then if I leave pubDate out of the RSS Item entirely it should probably be fine (given that this particular feed will always produce content starting with today and moving forward)?