A free program for Android, by Ngoc Aigner.

With the Free Messenger app, you do not only have a simple messaging tool, but you can also customize it just the way you want. It will surely protect your conversations and have real-time chitchat with your family and friends. There are various fonts and themes available so you will surely find one that suits your interest. It also has several ringtones in case you want to set a certain tone for a contact. In addition, you can also back up your messages to the cloud in case you accidentally deleted them.

This app is built to be simple to use so that you would not miss any updates from your contacts.