The app shall wake up once every 30 minutes. It shall not be active and use any battery except when it wakes up.
When it wakes up it shall call a predefined web server address with a https get command to fetch next command.
next command can be empty if there is nothing more to send or it can contain a phone number and a message text. This message text may be a single sms or a text longer than 160 characters.
After message is sent the app shall send result from the transmission to a different https address. And then request a new command, this continues until empty command is received.
This app shall work on android 9 and on android 8.
The web server already exists. It is only the android app that is included in the project. Full source code need to be delivered.