I am using Ghost 4.0 Casper theme and would like to remove the top-right ‘Subscribe’ button.
There is already a ‘Subscribe’ button in the bottom-right position and there is no need for two ‘Subscribe’ buttons.
You can view my publication at mcquinnreport.com, and the unnecessary top-right ‘Subscribe’ button can be seen on the homepage.
Here’s what you’re looking for 
Many thanks again Vikas!
For those who are wondering how to remove the floating button in the bottom-right position, it’s now in settings > portal (under ‘Members’) > ‘show portal button’ (on the left).
Is this still required?
I am unable to remove this. The “Show Portal button” option is no more there in the Labs in Settings.
The portal button is now controlled from ghost > settings (the gear icon) > membership