Medium migration template / Set older date on story

blog.xml

<?xml version="1.0" encoding="UTF-8" ?>

<rss version="2.0"
    xmlns:excerpt="http://wordpress.org/export/1.2/excerpt/"
    xmlns:content="http://purl.org/rss/1.0/modules/content/"
    xmlns:wfw="http://wellformedweb.org/CommentAPI/"
    xmlns:dc="http://purl.org/dc/elements/1.1/"
    xmlns:wp="http://wordpress.org/export/1.2/"
>

<channel>
    <wp:wxr_version>1.2</wp:wxr_version>

    <item>
        <title>Enter title here!</title>
        <pubDate>Wed, 18 May 2016 11:00:00 GMT</pubDate>
        <content:encoded>Enter your post's test here!</content:encoded>
        <wp:status>publish</wp:status>
        <wp:post_type>post</wp:post_type>
    </item>

    <item>
        <title>This is a second post, with an older date!</title>
        <pubDate>Tue, 03 May 2016 11:00:00 GMT</pubDate>
        <content:encoded>Post text goes here!</content:encoded>
        <wp:status>publish</wp:status>
        <wp:post_type>post</wp:post_type>
    </item>
</channel>
</rss>