Shamim's Plugins

you can use fep_get_new_message_button() and fep_get_new_announcement_number() function.

I actually did not understand your question. You want to change your avatar image?

if your php version 5.3+ add following code in you theme’s (child theme’s if any) functions.php

add_filter( 'fep_filter_display_participants', function(){
	$participants = get_post_meta( get_the_ID(), '_participants' );
	return implode( ', ', $participants );
	
});

this will show user id (as you suggested) in participants list.

Please check now.

Sorry for the inconvenience.
Did you update from any previous version? If yes, from which version?
Please let me know your php, mysql and wordpress version.

Give me admin access of your website and ftp access so that i can try.

Regards
Shamim

Are you updating from any previous version? Is it showing this error after update or all of a sudden?
Version 4.8 is stable and tested with wordpress version 4.4+ without any issue.
Can you please try again now?
Let me know.

Please go to front-end-pm-pro/pro/includes/class-fep-email-beautify.php line around 235 add $content['message'] = wpautop( $content['message'] ); just before return $content; line.

Let me know.

We are working for better email template system. we hope next version we will be able to introduce that.