Help please compiling Darktable 3 RC2

I compile Rawtherapee and want to have a look at Darktable so I thought I’d try to build it. I downloaded the RC2 tar.xz and things looked ok until I did the cmake. Mine is too old -

$ cmake -DCMAKE_BUILD_TYPE=Release …
CMake 3.10.0 or higher is required. You are running version 3.5.1

$ sudo apt-get install cmake
cmake is already the newest version (3.5.1-1ubuntu3).

I have only a fairly superficial understanding of linux. Is there a way round this? Should I try a PPA? Is it time to upgrade Ubuntu? - I am on 16.04 LTS.

Thanks for reading.

darktable 3.0.0 wont build on 16.04 anymore. (many libraries are too old)

you need 18.04 at least in which case you can just use the packages from here:

Various packages for darktable - master branch

Thanks, I’ll upgrade.