call simple html file from within post or page

Hi,
I looked for the whole forum but didn’t find any previous posts so I’m asking the question to my problem here.

Here is what I am trying to achieve.
In all my posts and pages, I have to insert a text at the end, the version number and every time we update the site, we have to change the version number and its a pain to go through hundreds of posts/pages.

So I thought I create the simple html file which I want to call from my posts and pages to insert the content on every page. So when the version number change, all I have to do it edit the html file and all pages will be updated. Instead of going through on every page. For version.html file example,
<strong>Created by "Prof. Name", Version 2.2</strong>

I put that file in root directory of the domain as its not that important and easily accessible.

So my questions is, how to achieve that? I read somewhere that to use the SSI method but found out, there are some restriction with PHP. Then one said I could use the following code but I’m keep getting PHP error.

<?php virtual ('http://domainname.com/version.html'); ?>

[insert_php]
<?php virtual ('http://domainname.com/version.html'); ?>
[/insert_php]

Can you help me in this please. Or guide me to correct method to do.

Thanks in advance.
Theticus

https://wordpress.org/plugins/insert-php/