[tuukkah]

As seen in the article, the invites are simple text files. (I haven't tried, but you might be able to create one with icalendar-export-region?)

I think the more difficult part is sending an email that looks and works right with the invite attached in a way compatible with the receiving systems.

Invitations from Microsoft systems are especially horrible as they look like normal, plain text messages (without an invite) in standards-compliant systems. Depending how the sender expresses themselves, the receiver might have no clue they were invited let alone the time and place.

[tuukkah]

I seem to have missed the author's point which is to craft the link and send the link to others to download. This way, it doesn't matter whatsoever what software is used.