Updating October CMS


Ive created a theme in Blocs that needs to work in October CMS. Which I have uploaded, activated and added content fine. But if I need to go back to blocs to change or modify the design of the website. When I re-export and apply the new theme all of the changes I made to the ‘content’ in October CMS in the previous theme is gone.

How do I update the theme without loosing all of my content?