The idea has been sitting in my head for a long time that it's time to get rid of this GSM with its billing depending on the destination of the call or text message. I just want a smartphone and unlimited Internet. Mobile Skype has already solved the issue of free calls to anywhere in the world, and the JaxtrSMS application will allow you to send SMS to any mobile number anywhere in the world for free, regardless of whether the recipient uses this program or not.
For the application to work, you only need to have the Internet on your mobile device. JaxtrSMS just clings to the address book and that's it. There are no restrictions on the number of messages. The most important thing is that the recipient will see your real mobile number, while sending messages through the operator's website or other services does not allow displaying the sender's number, forcing you to enter it in the message text.
Now about the cons: Cyrillic is not supported, but JaxtrSMS is still in beta status, so we should expect the addition of support for Cyrillic fonts in later versions. In addition to Android, there are versions of the application for iOS, Blackberry, Symbian, and soon, apparently, for WPM.