Under - Email newsletter (Send email to registered user)
You have the option - Select the email(s) from registered users list:
A,B,C D,E,F G,H,I J,K,L M,N,O P,Q,R S,T,U V,W,X,Y,Z
When you choose: "A,B,C" only user names that start with ABC are displayed.
This is very good if you have many users. By selecting an ABC group you can send email to users in batches.
There is one issue with this - I have users where the user name is a number. For example user name: 025345244
This user name is not visible under any of the current groups. Can you please add a group of "Numbers" ?