19 Jul 2017 Google advice: Switch Your M-Dot Domain to Responsive Before the Mobile-First Index Rollout
In November 2016, Google announced their mobile-first index initiative. Google has recently been sharing some tips and advice for webmasters.
Migrate your m-dot website to responsive before the launch
Google said that if you are looking to migrate your m-dot website to a fully responsive website, you should do so before the mobile-first index rolls out.
Right now, Google has a desktop-first index. Also, m-dot websites are not indexed properly. If you wait with updating your website and do it after the launch, then Google will fully index your m-dot websites. This means that migration to a responsive website will take longer, because Google is not going to just update URLs but also the content on your pages. It might be smart to think about migrating now, rather than waiting and doing it after the launch.