Is it safe to update Dazzling WordPress theme - will changes be lost?

Hi,

Once you update theme you will loose all customizations that you did inside theme files (PHP, CSS JavaScript).

Other things such as settings inside Theme Options or WordPress customizer will remain in place. Content itself such as images, videos, texts, comments, widget settings and everything else will remain in place.

If you want to make changes in the the template files you have to use Child Theme for that. A sample Dazzling Child Theme can be downloaded from here. If none of files are changed you can install updates without any problems.

Let me know if this helps.