Blockkit 1.2 is not compatible with older versions. For this reason you will need to reinstall all the files again.
Theme
Double click the theme to install it into Rapidweaver. It will have the name 'Block kit 1.2'. Use this theme with any new site.
Blocks
Drag the new set of blocks onto the page as you did with the previous version. The new blocks all have a 1.2 in the icon and a 1.2 in the name. Any blocks on the page of a website that you are updating need to be updated with these new versions.
Snippets
Install these as instructed in the easy and medium method. Once installed, their names start with 'Block kit 1.2'.
Asset files
If you are updating an old site to the new version make sure you link to the new version of add_to_assets supplied in Blockkit 1.2. If you installed the old add_to_assets in a theme, you need to replace them with this new version of add_to_assets.
html_text.txt
If you have modified the index.html page of a theme, you need to replace your changes with this new piece of code. The old code started with the line:
<link href="%pathto(css/add_to_assets/css.css)%" rel="stylesheet" type="text/css" />
and ended with the line:
//addCss(".db_menuContent,.db_infoboxContent{height: 0;}");
</script>
Find the old support pages for Blockkit1.1 here