Thank you for your followup!

Because the development of iPad version costs much but there are not many users, we've decided not to develop the version further.
Would you please use the phone version? iPhone version has been updated almost every month or two. And Android version, which is still in its test phase, has also been updated frequently. If you'd like to join the test on Android version, please just tell us.

Any further questions, please feel free to tell me.
Have a nice day!