But my guess is that the Europe might be replaced somewhere in the 2020's maybe, like Stena Danica for example, i might be wrong but when looking to the investments and refurbishing being made through the years i doubt it is an agenda for replacement, YET!
My thoughts is that the 1980's Stena vessels are about to go from 2020 . A little off topic, a photo was published somewhere, forgot the link. That there was a picture in the crew area telling this: "Stena Danica 1983-202?", which means that it is decided that it's going in a near future.
Let's not forget that apart from the Europe being oldest within Irish Sea fleet, most of the ferries in Scandinavia are one of the oldest within the Stena fleet:
Stena Saga: built in 1981, the same age as Europe
Stena Danica: built in 1983, two years younger only
Stena Nautica: built in 1986, just turned 30 years
Stena Vision: built in 1987, turning 30 years next year
Stena Spirit: built in 1988, 28 years old, only 2 years before the 30th anniversary