Since, Google has recently released an information that they are going to consider https over http as the preferable ranking signal, I'm in a plan to redirect all my http sites to https version. I could see that it is recommended by Google (https://googlewebmastercentral.blogspot.in/2015/12/indexing-https-pages-by-default.html) to implement HSTS header on my server along with this redirection. As we are currently in a shared hosting, is it possible for us to implement HSTS header in the server? If yes, Can anyone please help me on this with the HSTS header implementation procedure? We have been getting good enough backliinks as http for the past 7 years. So is it mandatory to redirect all those to https using .htaccess file now?