Yes I had to make up my mind whether to call it UTC or GMT. Because more people probably know the name GMT, and why change a name?
But sometimes names have to be changed, when an old one becomes outdated. So I decided to accept that we should use the term UTC.
In fact "Coordinated Universal Time" actually means something, whereas "Greenwich Mean Time" is really very obscure if you try to think about what the words mean. Also UTC has some standards attached, like it is always expressed in 24 hour format. I think 15:30 UTC is more clear than 3:30 PM GMT. So in the end I took the modern approach and chose to say UTC. I guess it is the future.