Change maximum file size for upload in Mantisbt

Let us imagine you need to upload large files into Mantis. For instance we will set a 40Mb limit.
First of all you need to change configuration option in Mantis itself:
$g_max_file_size = 40000000;

Then we change PHP variables:
upload_max_filesize = 40M
post_max_size = 40M

And at last it is necessary to change configuration of MySQL if you use it as a storage for files:
max_allowed_packet= 40M

After all these changes you will see the maximum file size in Report Issue page:
Upload File (Maximum size: 40,000k)

And do not forget to adjust max packet option for MySQLdump:

[mysqldump]
max_allowed_packet = 40M

Or your database backups will fail.