New trigger for registration

[pinochico]

This is a question for true connoisseurs / developers:

Starting with VM 3.8.4, the VM core development team changed the VM core code and moved the trigger for sending emails after user registration from the shopfunction.php file to the user.php model (perhaps for improved security?) With the words - This is life (Thanks Andrey

Now we need to return this feature, preferably using a trigger back to its original location to maintain the functionality of our 3d party extensions.

We have several options and we don't like either one very much (I'm not sure if I'll write them correctly):
- write a new system plugin that overrides the core VM model user - after each new version of the VM we have to release a new version again and again
- when installing our extension, load the core file of the user.php model and rewrite only those lines with the original code for sending emails to our code and save
- copy the whole user.php model to our extension (about 700 lines) and change it only by sending mails via sendVmMail ().
- break the treasury and pay to Max money to return the function
- break the treasury and pay to Max money to insert a new trigger into the user.php model

Can you advise me which variant is best to choose and where can I find more detailed information with an example?

Thank you for your time and direction