[2021] Maximum Duration of Private League?

The duration of a private league can't be extended beyond two months in length, which is why you can only add 50 days of duration upon the ten base days. You can extend the duration of the private league at any time once the league has started, but do note that if the parent challenge league ends, the private league will lose its challenge league properties and becomes parented to regular Standard or Hardcore. In saying that, we haven't quite confirmed the end date of Ritual but we do expect it to end early-mid April.

Just to provide further clarification, the maximum duration of a private league is 60 days regardless of when you extend it. For example: if you were to purchase the maximum extension of 50 days upon creating your private league, you would not be able to extend the duration halfway through the private league as it has already reached its 60 day maximum duration.