Switching an environment from Python 2 to Python 3ΒΆ

The command conda update moves up to the latest compatible version, while conda install can install any version.

EXAMPLE: If Python 2.7.7 is currently installed, but the latest version of Python 2 is 2.7.12 and the latest version of Python 3 is 3.5.2, then conda update python installs Python 2.7.12, while conda install python=3 installs Python 3.5.2.

Conda uses the same rules for other packages, so conda install always installs the highest version, and conda update always installs the highest version with the same major version number.