Please add lastmod tag to sitemap

The lastmod tag would help those of us writing blog content to drive web traffic for direct bookings to get it out to search engines more quickly.  Can you please add <lastmod> tag to the sitemap?  Years ago, Google may not have looked at this tag, but content is king nowadays for SEO ranking and OwnerRez claims to be good at that.  Bing states they do look at lastmod.

Also linking to this feature request for last updated date which is similar.