New IMSI messages

[REDACTED]

Hi. My son's phone suddenly started sending ""new IMSI" messages and I receive them on my phone. I uncheked the "send SMS to Portal" on MyAvast.com and then I deinstalled the Avast Antitheft as well. The phone still keeps sending the messages. Yesterday the phone sent 10 messages and these messages cost some money as well, especially if I get the count of 300 by the end of the month (I am abroad).
I changed the SIM card approx 5 months ago but then no messages were sent, phone got locked because of SIM change but I unlocked it.
Thank you.

[Eddy]

Disabling sending sms to the portal is not the same as disabling them for a "friends number".

https://blog.avast.com/2014/07/02/how-to-prevent-unnecessary-costs-of-avast-sms-notifications-when-replacing-your-sim-card/
http://files.avast.com/files/documentation/mobile-security-user-guide-en-v2-4-updated.pdf

[REDACTED]

Thank you for your answer. I did read this article and manual you are referring to before posting. My "friend list" is empty, "send SMS" to avast is off (both on the phone and on the website", "continuous tracking is off", sim card is on the "trusted SIM list". I uninstalled Antitheft but it kept sending the messages. I reinstalled Antitheft, "friend lis"t is empt and Antiteft disabled. My phone is connected to Avast web account and it shows there as well, that Antitheft is switched off. I am still using Avast Antivirus. The "New IMSI Messages" are still coming. I could not find any answer to my problem on either Google or Avast Forum. It all started just out of the blue. Any ideas.
Thank you again.

[Asyn]

Are you sure the message is from Avast..!?
Please post a screenshot.

[REDACTED]

Kind of, SMS comes with new IMSI and the IMEI of my son' s phone and it corresponds to the info that Avast says they will send if the SIM card is changed (it was changed 5 months ago and it is on the trusted SIM list now). I do not see a reason for any other program doing that. I set the phone on the flight mode and messages stopped coming. It is kid's phone and there are bunch of games, Facebook, e-mail (none associated with my phone number) and then Avast.
Thanks for looking into it.

[Eddy]

I uninstalled Antitheft but it kept sending the messages.

Just some basic logic.
If it was removed it can't send messages.
The picture shows no evidence and not even a indication that it is avast who is sending the sms's.

I would say reset to device to manufacturers default.
If it is rooted, you will need to undo that first.

[REDACTED]

Thanks, I will go for reset. However, Avast says as well that in case of SIM change the phone itself will send a SMS as well so I would know the new number of the phone (if it is stolen). That is the case now, the phone is sending those IMSI messages. Yes I agree with you that it is basic logic that if the program is deactivated or uninstalled then it will not send an SMS or perform in any other way...you never know.
Thanks again for your time.

[Asyn]

Eddy is right, these are definitely no msgs from Avast.
Note: Some devices come preinstalled with similar tools.