BC Template Update Available

Several questions regarding Templates -

1. Currently I noticed an 'update to new version' available in control panel and wondered if anyone knew what the 'update' relates to? (Homewares-brown)  I could not find any info about it - concerned about updating in case 'reverting' doesn't work  :)
2. I see all the new 'themes' available and not quite sure what they mean - Style Editor vs Responsive?
3. Since about end of March there has been a drastic change in Mobile Orders  (based on icon showing in Order Panel) Mobile Phone now non-existent and iPad/Android down considerably. Google Analytic shows mobile traffic down 75%.
4. On May 10, someone abandoned an Order after 3 attempts (which I might conclude they wanted to place the order rather than not liking the terms and actually abandoning.
   

At the early stages of website transfer (Jan-March) we registered a good balance of mobile activity without issue. I use a tracking code for website tracking and in that profile it also showed all traffic back then. It is no longer showing and they (the other company) is telling me I need to install on the mobile template.

In Jan/Feb? when we had access to BC directly, there was a change the tech said 'created an unexpected consequence' and he was kind enough to go into the mobile template and make a minor change (on order e-mail). Activity and Statistics/Web Monitoring continued to register after this - but no longer.

Confused as to why all the mobile stats have changed so drastically.

Appreciate your insight.