Development Environment
LEAN Engine Versions
Introduction
The latest master branch on the LEAN GitHub repository is the default engine branch that runs backtests, research notebooks, and live trading algorithms. The latest version of LEAN is generally the safest as it includes all bug fixes. Trading Firm or Institution tier users concerned for stability can elect to use older or custom versions of LEAN.
Change Branches
Follow these steps to change the LEAN engine branch that runs your backtests and live trading algorithms:
- Open a project.
- In the left navigation menu, click the
QuantConnect icon.
- In the Project panel, click the LEAN Engine field and then click a branch from the drop-down menu.
- (Optional) Click to display the branch description.
- If you want to always use the master branch, select the check box.
- Click .
Changing the Lean engine branch only affects the current project. If you create a new project, the new project will use the master branch by default.
Custom Branches
To create and use custom versions of LEAN, see Custom Docker Images.