First of all I'd like to suggest upgrading to the newest version of the Tigase - just the other day we released version 8.1.0.

Regarding issue at hand - there is no ready-made solution to migrate data between various databases. It would definitely be possible to create such tool. As an inspiration you could take a look at https://github.com/tigase/tigase-database-migrator (which converts data from ejabberd to Tigase, but it should be relatively strightforward to create custom converter that woulc convert from Tigase to Tigase) or Converter.java class that upgrades MUC component, but the idea is the same - initialised component repository with the JDBC URL - in your case it would be two instances of the current version of the repository and then you would iterate over items from old repository (mysql) and insert in the new one (mongodb).

Of course you can contact us directly here: https://tigase.net/technical-support if you would like assistance of the Tigase Team.

Thank you for your quick response. I understood you, and for now I will close this question. Thank you. Regards.