sudo apt purge cmake
sudo apt autoremove

Downloading the new

https://cmake.org/files/v3.11/cmake-3.11.1-Linux-x86_64.sh
sudo mkdir /opt/cmake
sudo sh cmake-3.11.1-Linux-x86_64.sh --prefix=/opt/cmake --skip-license

Make it available

sudo update-alternatives --install /usr/bin/cmake cmake /opt/cmake/bin/cmake 1 --force