python not using latest numpy version
You should use a virtual environment. Your system most likely will default to the most up to date version. 
Try installing:
pip install virtualenv 
then run:
virtualenv -p python2.7 environment_name. 
Source the virtualenv with:
source environment_name/bin/activate 
then pip install numpy=1.14.2.
Then you will have a mini environment with the exact version you want and wont update. This way you can have multiple versions all contained in the same system.
I have a problem.
I need numpy 1.14.2, and my machine (Linux Mint 17.3) has only 1.8.2 installed.
I then installed 1.14.2 through pip. But when I load it in ipython, it still says that it is 1.8.2.
Using yolk I saw that 1.14.2 is actually installed, but marked as non-active.

numpy           - 1.14.2       - non-active development
  (/usr/local/lib/python2.7/dist-packages)

While for 1.8.2 it says "active".
Also, 1.8.2 is located in "/usr/lib/python2.7/dist-packages/numpy".
Why is there a difference? I dont see a reason why there are two libraries.
I read that python loads the libraries by the order in $PATH.
And indeed, when I look at sys.path, I see that /usr/lib... is listet before /usr/local ....
How can I change that? I dont have anything in .bashrc, /etc/profile or /etc/rc.local which would set this specific order.
Thx.