What happens if we don't make that template change? What adverse effects are there? I just know I will be updating to 3.6 eventually and prefer to change the templates as little as possible.

If you don't make the template change then the users won't be able to see an option for instant email notification when they subscribe to a forum. In other words, the mod won't work.

I've installed this in my 3.6.1 forum (recently upgraded all the way from 2.3.5!). In my old installation, I had hacked to automatically subscribe to new threads that are created within forums to which you are subscribed and also send email notification of the first post of the new thread. This add-on did almost exactly what I needed in the upgraded forum.

I did modify this a bit in my installation. Like others, I wanted that initial post emailed out with the body of the message and wanted instant email subscribers to forums to receive email copies of ALL posts in the new threads, not just the opening post of a new thread. I also wanted the email notification of the new thread opening post to look the same as the email notification for all subsequent posts.

My method of achieving this was to make the template change as specified, modify the foruminstantnotify phrases for email subject & body text to match those found for the notify phrases (with minor variable changes below), and modify the plugin code as per the attached file.

The plugin change grabs the username of subscribed users for use in the email notification and adds an insert query to add a thread subscription for each forum instant subcriber found.

The changes to the email body notify phrase that need to be made when copying to the email body foruminstantnotify phrase are:

change $pagetext to $newpost[message]
change $touser[username] to $subscribe[username]

Worked for me... maybe it will also work for others looking for similar results.

This is not working with 3.6.1.

This is what I get after removing the If statement

The following error occurred when attempting to evaluate this template:

The conditional on line 28 appears to be missing its end tag (</if>). The template will not function properly unless this is fixed.

This is likely caused by a malformed conditional statement. It is highly recommended that you fix this error before continuing, but you may continue as-is if you wish.

If I ignore the error then I can no longer subscribe to threads

Was working okay for me with 3.6.4. Still, here's a newer one, with more features, supported up to 3.6.5 currently.

works on 3.7.2 :)