See release and update notes - https://earthgecko-skyline.readthedocs.io/en/latest/releases/1_2_9.html
https://github.com/earthgecko/skyline/blob/master/docs/releases/1_2_9.rst
Security update in-situ
Update Python requests library to 2.20.0 for CVE-2018-18074, a manual update of the requests version is possible in-situ without needed to deploy the full release, in your Skyline Python venv simply activate the venv and run:
bin/pip2.7 install requests==2.20.0