Every non Thai citizen staying in the Kingdom for 90 consecutive days need to fill the 90 days report. The problem is... you are likely to have to calculate yourself when are you due!
This simple app will calculate it with you, including what are the time ranges for the report by mail, the report online and the report at the immigration offices. All you have to do is chose when did you arrive to Thailand. Also, for subsecuent reports you can specify your due date to calculate the deadlines.
The application will remember your arrival date, so you can open it again to check if the dues are getting closer without needing to enter it again.
You have the option to add the information to your calendar application for better convenience or setting reminders.