The master branch is now reopened for new features and so on. If you want keep a stable state of your i-MSCP installation, we recommend you to not try to update to last master branch.
A specific branch named first-stable has been created for the maintenance of the first stable release. You can update your installation with it if you want get fixes before the official maintenance releases.
For those that are not afraid to use the current development branch, they can still use the master branch either to install or update but keep in mind that you will not be able to go back.