We implement your plugin successfully in one of our sites. We used to send notification messages to all our members, but recently the site increase their members registration and go over 300 and our notification message stuck and gets timeout.
Which is the limit on this bulk send? There is some that we can do about it to succefull sent to all members?
How you send announcement to custom selected users? When you go to Front End PM PRO > New Announcement in right sidebar there is option to select role(s). You can create a temporary role with users to whom you want to send announcement then you can select that role from right sidebar when create announcement.