I was just checking my Shopify Development store admin and found that Shopify has released a few OS 2.0 themes, which are based on Dawn 2.0 theme. Though, these new themes have some new features and enhancements that you might like and Dawn OS 2.0 Version 2.5 did not have. Also, I could see some style improvements too and mobile first design approach.
Shopify Sense Theme Customization
Here is a quick video on customizing Shopify Sense OS 2.0 theme, you might find it useful to watch this video before you customize your Sense theme ot switch to Sense theme.