The split concerned which version of ECMAscript was next: one side advocated ECMAscript 3.1 as an evolution of the existing ES3 standard while the other side wanted to move to a new major revision, ECMAScript 4.
A proposal, dubbed "Harmony" by Eich, has brought the two sides together after a meeting held in July. The meeting in Oslo resolved to focus work on ECMAScript 3.1. The aim is now to have two interoperable implementations of ES3.1 by early next year. Alongside this, there will be collaboration between the committee members to develop a less radical, more modest next step beyond ECMAScript 3.1.
As part of the new deal, a number of ECMAScript 4 proposals, such as packages, namespaces and early binding, have been declared "unsound for the web" and have been taken out of the specification process for good. The language of ECMAScript 4 goals is also being reworded to fit a new consensus position.
In announcing the agreement, Eich said "Much work remains on 3.1 and Harmony, but we are now on a good footing to make progress as a single committee."