How to view already deleted messages?

Question

Data recovery

I have Viber messages that have been deleted. Even before I downloaded the recovery app. The fact is that these recovery applications are designed for the fact that after installing them, I will definitely delete something. And I need an application that would find deleted messages that were deleted when I did not have this application on my phone.

Answer 1

99% nothing

Answer 2

which were deleted when I did not have this application on my phone.

Think for yourself, what then to restore if there was no application, which means that the message never got to the phone, from what to restore?
There is a 100%
chance that viber provides such functionality, but this is unlikely (look for if viber has a program to get all the data that the company has collected about you in the form of a dump, whatsup has, in theory there will be deleted messages)

Answer 3

these recovery applications are designed to ensure that after installing them I will definitely delete something

You are describing backup applications.

I need an application that would find deleted messages that were deleted when this application was not on my phone

All normal data recovery programs work this way. They analyze the drive and look for what is left alive. You don't need to set them up ahead of time.
In your particular case (recovering Viber messages from your phone), I see two options:

1. I have never used Viber, but whatsapp keeps 7 or 8 latest messages database. If you deleted recently and there are such backups in Viber, roll back to a suitable date, and then return to the most recent one. Or restore the one you need on another device, if such a trick does not violate the internal synchronization in any way. Also check if you have any other backups configured (to Google Drive, etc.).
   
2. Contact the experts. If you go this way, then the sooner the better, and before that, the phone should be turned off altogether so as not to overwrite the necessary. You need a company that has tools like Cellebrite UFED or Mobile Forensic. More simple "laptop repairs" will not be able to help. In order not to fall for scammers, look at this brief memo on choosing a normal company: Data Recovery.rf