How to update anaconda distributions and python packages?

Question

I have a anaconda distribution installed on a OS X system.

If I look at the packages installed with anaconda navigator, I see that lots of package are upgradable. If I upgrade one of them, then I have a anaconda package in the list with the version custum. If I upgrade this package I came back to the previous version of the packages I have upgraded previously.

Hereafter, I followed this page of the documentation.

--> conda update conda
Fetching package metadata .......
Solving package specifications: ..........

Package plan for installation in environment /blabla/anaconda:

The following packages will be UPDATED:

    anaconda: 4.2.0-np111py35_0 --> custom-py35_0
    conda:    4.2.13-py35_0     --> 4.2.14-py35_0
    requests: 2.11.1-py35_0     --> 2.12.4-py35_0

Proceed ([y]/n)? y
...
[      COMPLETE      ]

--> conda update anaconda
Fetching package metadata .......
Solving package specifications: ..........

Package plan for installation in environment /blabla/anaconda:

The following packages will be UPDATED:

    anaconda: custom-py35_0 --> 4.2.0-np111py35_0

The following packages will be DOWNGRADED due to dependency conflicts:

    conda:    4.2.14-py35_0 --> 4.2.13-py35_0
    requests: 2.12.4-py35_0 --> 2.11.1-py35_0

Proceed ([y]/n)? y
...
[      COMPLETE      ]

As you can see, with update conda, conda and request are updated to a newer version and with update anaconda, the same packages are downgrade to an older version.

Thus my question is, given a current installation of anaconda, what should I do if I want to maintain packages and update the whole distribution ?

Solution

This will update all packages:

conda update --all

Comments

[IanSR]

The answer by Mike is correct in 95% of cases, but since this is a common question and the apparently obvious answer (conda update anaconda, which normally you should not execute) leads to unexpected and undesireable results (such as actually downgrading packages), I have provided a longer discussion of this question here: stackoverflow.com/questions/45197777/how-do-i-update-anacond‌​a

[Pigeon]

conda update conda didn't work in for me. This did. :)