If I update through ftp then I'll lost my settings and configuration etc ?
I should overwrite old files of Modern theme
or
I need to delete old theme files first then upload updated theme through ftp ?
How to Update Modern theme:
1) Copy any/all the “code” changes you’ve done in the theme. Mostly in the functions.php file. If you have not made any changes in the modern theme then ignore this step.
2) Download the modern theme.
3) Upload it in your server at wp-content/themes location.
4) Remove the wplms_modern folder in your current theme.
5) Upload and unzip the .zip file in your server.
6) Done.