How to increase the number of characters for Bitrix24 extensions?

Question

1C-Bitrix

Boxed version. We have 5-digit extensions in the company.
And Bitrix allows you to add from 1 to 4 characters.
In the settings it was not possible to find, technical support says that in standard solutions there is no such possibility yet, increasing the characters.
But since we have a box, files are available for editing.
Is it somehow possible to edit the value somewhere, in some database table or in Bitrix files?
Thank you.