You'll have to let go of YouTube's older interface if you've been reticent to try the 2017 redesign. YouTube has warned that it's dropping the classic web interface in March, almost three years after its official replacement. The video behemoth isn't shy about the reasoning: legacy versions are now missing many of the features and tweaks that have crept in since the current version launched.
If you are holding on to the older version, you'll see a notice asking you to switch. YouTube will also let you know if your browser is too old or otherwise won't support the modern interface. This could leave some viewers in a tough spot if they can't upgrade their software, but YouTube is no doubt betting that there are few viewers who'll be left behind.